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A   MANUAL   OF 
DETERMINATIVE  MINERALOGY 

WITH  TABLES 

FOR  THE  DETERMINATION  OF  MINERALS 

BY  MEANS  OF: 

I.  THEIR  PHYSICAL  CHARACTERS 
II.  BLOWPIPE  AND  CHEMICAL  PROPERTIES 


BY 

J.  VOLNEY  LEWIS 

Professor  of  Geology  and  Mineralogy  in  Rutgers  College, 
State  University  of  New  Jersey 


Third,  Revised  and  Enlarged  Edition 

TOTAL   ISSTJE   SIX   THOUSAND 


NEW  YORK 

JOHN   WILEY  &   SONS,   INC. 

LONDON:  CHAPMAN  &  HALL,  LIMITED 
1921 


COPYBIGHT,    1912,    1915,    1921 
BY 

J.  VOLNEY  LEWIS 


BRAUNWORTH   &  CO. 

BOOK  MANUFACTURERS 

BROOKLYN,    N.  Y. 


PREFACE  TO  THE  THIRD  EDITION 


IN  this,  the  third,  edition,  the  blowpipe  tables  have  been  thor- 
oughly revised  and  recast  and  a  new  classification  of  minerals  based 
on  their  physical  properties  has  been  added.  These  two  sets  of 
tables  are  largely  complementary,  and  cross-references  have  been 
inserted  in  order  to  facilitate  their  use  as  a  check  upon  each  other. 

The  blowpipe  tables  include  about  355  minerals  and  the  physical 
classification  about  290.  Species  that  have  been  omitted  are  very 
rare  and,  from  the  practical  point  of  view,  of  no  importance.  The 
book  is  thus  adapted  to  the  requirements  of  the  geologist  and 
engineer,  as  well  as  the  student. 

The  higher  degree  of  accuracy  attained  in  the  determination  of 
minerals  by  means  of  blowpipe  and  chemical  tests  is  generally  recog- 
nized, but  in  practice  the  necessary  appliances  are  not  always  available. 
Furthermore,  the  experienced  engineer  and  geologist  may  often  save 
time  by  reference  to  the  physical  classification.  Such  tables  have 
peculiar  value  for  the  student  also,  since  they  require  close  and  accu- 
rate observation  of  streak,  hardness,  color,  luster,  form,  and  cleavage, 
and  because  of  the  emphasis  they  place  on  occurrence  and  mineral 
associates.  By  their  use  the  student  acquires  a  practical  acquaint- 
ance with  minerals  that  is  of  great  value  in  sight-recognition. 

The  classification  according  to  physical  characters  departs  radi- 
cally from  the  common  practice  in  the  construction  of  physical  tables 
in  that  luster,  so  often  a  matter  of  uncertainty,  has  been  entirely 
eliminated  as  a  basis  of  classification.  This  keeps  down  the  bulk 
of  the  tables  somewhat,  and  to  that  extent  facilitates  their  use,  by 
avoiding  excessive  repetition. 

Determinations  based  on  physical  characters  often  require  con- 
firmatory blowpipe  tests,  however,  and,  in  the  author's  opinion, 
nothing  can  take  the  place  of  thorough  drill  for  the  student  in  blow- 
pipe and  chemical  methods  and  in  the  use  of  tables  based  upon  them. 
Chemical  composition  is  the  most  fundamental  property  of  minerals, 
and  many  species,  particularly  among  the  ores,  can  be  determined 
with  certainty  only  by  means  of  chemical  tests. 

iii 


iv  PREFACE  TO  THE  THIRD  EDITION 

In  the  blowpipe  tables  the  general  plan  of  von  Kobell,  as  adapted 
and  revised  by  Brush  and  Penfield,  has  been  followed,  but  with  much 
condensation  and  simplification  of  procedure  and  also  with  extensive 
rearrangement,  especially  among  the  nonmetallic  minerals.  Chem- 
ical formulas  and  descriptions  of  physical  properties  have  been  thor- 
oughly revised  and  several  new  species  have  been  added.  In  general 
blowpipe,  or  "  dry,"  tests  have  been  preferred  to  those  made  in  the 
"  wet "  way. 

A  brief  summary  of  physical  mineralogy  precedes  the  physical 
tables,  and  the  text  that  precedes  the  blowpipe  tables  has  been 
largely  rewritten.  Several  new  illustrations,  drawn  from  photo- 
graphs of  the  actual  operations,  are  expected  to  reduce  the  labor  of 
individual  instruction  in  the  details  of  laboratory  technique.  The 
classification  of  minerals  according  to  crystallization  has  been  revised 
and  the  glossary  has  been  rewritten  and  enlarged.  In  the  interest  of 
efficiency  these,  together  with  the  list  of  abbreviations  and  the  table 
of  chemical  elements,  have  been  placed  at  the  end  of  the  book. 

It  is  intended  that  the  use  of  the  tables  shall  not  only  furnish  a 
name  by  which  a  mineral  may  be  called,  but  shall  also  lead  the  student 
to  acquire  a  first-hand  knowledge  of  what  the  mineral  really  is,  both 
chemically  and  physically.  The  constant  use  of  a  good  treatise  on 
descriptive  mineralogy  to  supplement  the  tables  is  strongly  recom- 
mended. The  instructions  and  precautions  accompanying  both  the 
physical  classification  and  the  blowpipe  tables  will,  it  is  hoped,  prove 
adaptable  and  serviceable.  They  are  intended  to  aid  the  student 
in  the  development  of  habits  of  neatness,  orderliness,  and  accuracy, 
and  at  the  same  time  to  inculcate  a  certain  respect  for  mineral 
specimens,  which  are  so  easily  damaged  or  destroyed,  but  which 
cannot  be  reproduced. 

Again  I  gratefully  acknowledge  my  indebtedness  to  my  fellow 
instructors  in  various  parts  of  the  country,  of  whose  kindly  criticism 
and  helpful  suggestions  I  have  been  glad  to  avail  myself  in  the  prepa- 
ration of  this  revised  edition. 

J.  VOLNEY  LEWIS. 

NEW  BRUNSWICK,  NEW  JEESET, 
December,  1920. 


CONTENTS 


PAGE 

PROPERTIES  OP  MINERALS 1 

Crystallization 1 

Physical  Properties 6 

Chemical  Properties 10 

PHYSICAL  TABLES 12 

General  Classification 13 

DETERMINATION  BY  BLOWPIPE  TESTS 151 

Apparatus 151 

Reagents 7 154 

Blowpipe  Operations  and  Chemical  Tests 156 

Reactions  of  the  Elements 174 

BLOWPIPE  TABLES 191 

Laboratory  Records 193 

General  Table 194 

MINERALS  CLASSIFIED  ACCORDING  TO  CRYSTALLIZATION 266 

GLOSSARY 275 

ABBREVIATIONS ! 285 

CHEMICAL  ELEMENTS 286 

INDEX 287 


DETERMINATIVE  MINERALOGY 


PROPERTIES    OF    MINERALS 

Definition. — A  mineral  is  a  natural  substance  of  definite  chemical 
composition  produced  by  inorganic  processes  and,  with  few  excep- 
tions, crystalline  in  structure.  When  crystallizing  under  favorable 
conditions  minerals  take  the  form  of  crystals  bounded  by  plane 
surfaces,  and  all  crystals  of  the  same  substance  possess  the  same 
degree  of  symmetry  and  the  same  fixed  angles  between  corre- 
sponding faces. 

Many  minerals  are  definite  compounds  only  in  the  sense  of 
varying  between  fixed  limits,  according  to  well-defined  chemical 
principles  (see  Isomorphism,  p.  11).  A  few  like  opal  and  chryso- 
colla,  are  amorphous,  or  noncrystalline,  and  widely  variable  in 
composition.  Although  included  among  minerals,  such  substances 
are,  strictly  speaking,  not  definite  mineral  species. 

In  contrast  with  the'  definiteness  of  minerals,  rocks  generally 
are  aggregates  of  two  or  more  minerals;  some,  however,  like  lime- 
stone and  sandstone,  are  composed  chiefly  of  one, 

CRYSTALLIZATION 

The  Six  Systems. — Crystals  give  outward  expression  to  the  sym- 
metry of  the  internal  molecular  structure.  All  crystals  may  be 
grouped  under  six  systems  of  crystallization.  These  are  distinguished 
from  one  another  by  differences  in  symmetry,  expressed  in  terns  of 
directions  and  relative  lengths  of  certain  lines  assumed  through  the 
center  of  the  crystal  and  called  crystallographic  axes.  Thus: 

1.  Isometric,  having  three  equal  axes  at  right  angles  to  one 
another.  (See  Figs.  1  to  20.) 


2 


PROPERTIES  OF   MINERALS 


2.  Tetragonal,  having  three  axes  at  right  angles,  two  of  which 
are  equal  and  the  third  shorter  or  longer.     (Figs.  21  to  29.) 

3.  Orthorhombic,  with  three  axes  at  right  angles,  all  unequal. 
(Figs  30  to  37.) 

4.  Monodinic,  with  three    unequal  axes,  two  inclined  to  each 
other  and  the  third  at  right  angles  to  these.     (Figs.  38  to  44.) 

5.  Triclinic,  three  unequal  axes,  all  inclined.     (Figs.  45,  46.) 

6.  Hexagonal,  having  three  equal  axes  in  one  plane  and  inclined 
at  angles  of  60  degrees  to  one  another,  with  a  fourth  at  right  angles 
to  these  and  shorter  or  longer.     (Figs.  47  to  58.) 

Twin  crystals  are  symmetrical  groups  of  two  individuals  (or 
more  in  case  of  repeated  twinning),  which  may  be  simply  in  contact 
(contact  twins,  see  Figs.  29  and  39)  or  may  penetrate  each  other 
(penetration  twins,  see  Figs.  12,  32,  33,  and  43). 


FIG.  9. 


FIG.  10. 


FIG.  11. 


FIG.  12. 


ISOMETRIC  CRYSTALS:  Fig.  1,  Octahedron  (111);  2,  Trisoctahedron  (221); 
3,  Trapezohedron  (211);  4,  Hexoctahedron  (321);  5,  Cube,  or  hexahedron  (100); 
6,  Tetrahexahedron  (210);  7,  Dodecahedron  (110);  8,  Combination  of  dodeca- 
hedron and  trapezohedron ;  9,  Combination  of  cube  and  octahedron;  10,  Com- 
bination of  cube,  octahedron,  and  dodecahedron;  11,  Combination  of  octahedron 
and  dodecahedron;  12,  Twinned  cubes  (a  penetration  twin). 


CRYSTALLIZATION 


FIG.  13. 


FIG.  14. 


FIG.  15. 


FIG.  16. 


FIG.  17. 


FIG.  18. 


FIG.  19. 


FIG.  20. 


ISOMETRIC  CRYSTALS:  Fig.  13,  Tetrahedron  (111);  14,  Tristetrahedron  (211); 
15,  Deltohedron  (221);  16,  Hextetrahedron  (321);  17,  Combination  of  tetra- 
hedron and  tristetrahedron  (tetrahedrite) ;  18,  Pyritohedron  (210);  19,  Diploid 
(321);  20,  Combination  of  cube  and  pyritohedron  (pyrite). 


FIG.  21.  FIG.  22.  FIG.  23.  FIG.  24.  FIG.  25. 


FIG.  26. 


FIG.  27. 


FIG.  28. 


FIG.  29. 


TETRAGONAL  CRYSTALS:  Fig.  21,  Pyramid  of  the  first  order  (111);  22,  Pyra- 
mid of  the  second  order  (101);  23,  Ditetragonal  pyramid  (212);  24,  Ditetragonal 
prism  (210);  25,  Prism  of  the  first  order  (110);  26,  Prism  of  the  second  order 
(100) ;  27,  Combination  of  first  order  prism  and  pyramid  with  second  order  prism 
(vesuvianite) ;  28,  Combination  of  basal  pinacoid  with  the  same  forms  as  Fig.  27 
(vesuvianite) ;  29,  Twin  crystal  of  cassiterite  (a  contact  twin). 


PROPERTIES  OF  MINERALS 


FIG.  30. 


FIG.  31. 


FIG.  32. 


FIG.  33. 


FIG.  34. 


FIG.  35. 


FIG. 


FIG.  37. 


ORTHORHOMBIC  CRYSTALS:  Fig.  30,  Combination  of  pinacoids  (100),  (010), 
and  (001);  31,  Combination  of  basal  and  brachy  pinacoids  with  prism  (110)  and 
macro  dome  (101)  (staurolite) ;  32,  33,  Penetration  twins  (staurolite) ;  34,  Pyra- 
mid (111)  (sulphur);  35,  Combination  of  pyramids  (111)  and  (113)  (sulphur); 
36,  Combination  of  prism,  pyramid,  domes,  and  pinacoids  (olivine);  37,  Com- 
bination of  prism,  domes,  and  basal  pinacoid  (celestite). 


1 


FIG.  38. 


FIG.  39. 


FIG.  40. 


FIG.  41. 


FIG.  42. 


MONOCLINIC  CRYSTALS:  Fig.  38,  Hemipyramid  (111),  prism  (110),  and  clino 
pinacoid  (010),  in  combination  (gypsum);  39,  Contact  twin  (gypsum);  40,  Com- 
bination of  hemipyramids  (111)  (221),  prism  (110),  and  pinacoids  (100),  (010) 
(pyroxene);  41,  Combination  of  same  forms  with  basal  pinacoid  (001)  (pyroxene); 
42,  Combination  of  prism  (110),  pinacoids  (010)  (001),  and  hemi-ortho  domes 
(101)  (201)  (orthoclase). 


CRYSTALLIZATION 


FIG.  43. 


FIG.  44. 


FIG.  45. 


FIG.  46. 


MONOCLINIC  CRYSTALS:  Fig.  43,  Penetration  twin  (orthoclase) ;  44,  Prism 
(110),  pinacoids  (010)  (001),  and  hemi-ortho  dome  (201)  (orthoclase). 

TRICLINIC  CRYSTALS:  Fig.  45,  Combination  of  tetra-pyramids  (111)  (111), 
hemi-prisms,  (110)  (110),  macro  pinacoid  (100),  and  macro  dome  (201)  (axinite); 
46,  Combination  of  brachy  pinacoid  (010),  basal  pinacoid  (001),  hemi-prisms 
(110)  (110),  and  tetra-pyramids  (111)  (III)  (albite). 


FIG.  47.  FIG.  48. 


FIG.  50. 


FIG.  51. 


FIG.  52. 


FIG.  53. 


FIG.  54. 


HEXAGONAL  CRYSTALS:  Fig.  47,  Pyramid  (1011);  48,  Dihexagonal  pyramid 
(2131);  49,  Prism  (1010);  50,  Dihexagonal  prism  (2130);  51,  Combination  of 
prism  and  pyramid;  52,  Rhombohedron  (lOll)  (calcite),  53,  Rhombohedron 
(0221)  (calcite);  54,  Combination  of  the  two  preceding  rhombohedrons  (calcite). 


PROPERTIES  OF  MINERALS 


FIG.  55. 


FIG.  56. 


FIG.  57. 


FIG.  58. 


HEXAGONAL  CRYSTALS:  Fig.  55,  Scalenohedron  (2131)  (calcite);  56,  Combi- 
nation of  scalenohedron  and  rhombohedron  (calcite) ;  57,  Combination  of  rhom- 
bohedron  (Oll2)  and  prism  (calcite);  58,  Hemimorphic  crystal  (tourmaline). 

In  the  absence  of  crystals,  evidence  of  crystalline  structure  and 
symmetry  may  often  be  observed  in  the  development  of  cleavage 
or  parting  in  the  broken  material. 


PHYSICAL  PROPERTIES 

Crystal  aggregates,  although  lacking  the  definite  symmetry  of 
twin  groups,  may  possess  a  high  degree  of  regularity,  as  in  radiating, 
globular,  and  plumose  forms.  In  some  aggregates  the  individuals 
are  well-formed  crystals  at  free  ends  or  sides,  but  in  many  they  are 
so  closely  crowded  upon  one  another  as  to  fill  the  whole  space. 
This  condition  gives  rise  to  coarse  or  fine  granular  texture  and,  where 
the  individuals  are  microscopic  in  size,  to  dense  masses. 

Cleavage  is  the  capacity  possessed  by  many  minerals  for  breaking 
with  smooth  planes  parallel  to  certain  actual  or  possible  crystal  faces, 
as  in  the  basal  cleavage  of  the  micas,  the  rhombohedral  cleavage  of 
calcite,  and  the  cubic  cleavage  of  galena.  Minerals  that  break  with 
ease  in  such  directions,  like  the  examples  named,  yielding  smooth 
lustrous  faces,  are  said  to  have  perfect  cleavage.  Inferior  degrees 
are  termed  distinct,  indistinct,  imperfect,  etc.  Both  the  direction 
of  cleavage  and  the  ease  with  which  it  may  be  developed  are  fixed 
properties  of  the  species,  and  hence  important  in  determination. 

Cleavage  planes,  in  contrast  with  crystal  faces,  are  commonly 
more  or  less  splintery;  and  the  simultaneous  reflection  of  light  from 
numerous  small  areas  often  reveals  the  presence  of  cleavage  where 
no  conspicuous  flat  surface  is  seen. 

Parting  resembles  cleavage,  but  shows  this  important  difference: 
th3  capacity  for  breaking  with  smooth  surfaces  is  limited  to  certain 
definite  planes  along  which  weakness  has  been  developed  by  strain 


PHYSICAL  PROPERTIES  7 

or  by  twinning  lamellae.  Hence  one  crystal  may  have  parting  while 
another  of  the  same  mineral  may  have  none;  and  even  where  it  is 
developed  the  portions  between  the  parting  planes  do  not  possess  the 
capacity  for  breaking  in  this  manner. 

Fracture  is  the  term  applied  to  breaking  that,  unlike  cleavage 
and  parting,  does  not  produce  smooth  planes.  Common  forms  are  de- 
scribed as  uneven,  yielding  a  rough  or  irregular  surface;  conchoidal, 
breaking  with  curved  surfaces,  often  with  concentric  markings  like 
a  shell;  hackly,  giving  sharp,  jagged  surfaces,  like  broken  metal; 
splintery,  producing  elongated  splinters,  commonly  due  to  fibrous 
or  columnar  structure;  and  earthy,  breaking  like  clay  or  chalk. 

Hardness  is  resistance  to  abrasion,  or  scratching,  and  is  commonly 
designated  approximately  by  numbers,  according  to  the  scale  of 
hardness  devised  by  Mohs,  as  follows: 

1.  Talc  6.  Orthoclase 

2.  Gypsum  7.  Quartz 

3.  Calcite  8.  Topaz 

4.  Fluorite  9.  Corundum 

5.  Apatite  10.  Diamond 

Intermediate  values  are  expressed  as  one-half  (as  3|  or  3.5,  etc.). 
Closer  determinations  are  seldom  attempted.  Approximate  hard- 
ness can  often  be  determined  conveniently  by  noting  the  ease  or 
difficulty  with  which  a  mineral  scratches  or  is  scratched  by  one  of 
the  following: 

Thumb  nail,  1\  Emery  (wheel  or  paper),  8-9 

Copper  or  silver  coin,  3  Corundum  or  alundum  (wheel, 
Knife  blade,  5|-6  paper,  or  whetstone),  9 

Window  glass,  5|-6  Carborundum  (wheel,  etc.),  9| 

File,  6|-7  Diamond  (glazier's  point),  10 
Quartz  or  flint,  7 

With  practice  hardness  can  be  closely  estimated  with  the  knife 
alone.  Rubbing  on  a  fine-cut  file  is  sometimes  convenient;  a  soft 
mineral  yields  much  powder  and  little  noise,  and  vice  versa.  Hard- 
^ness  must  be  tested  on  a  sound  surface,  and  brittleness  must  not  be 
confused  with  softness.  Fibrous,  scaly,  granular,  and  pulverulent 
masses  often  crumble  easily  and  seem  much  softer  than  they  are.  A 
few  minerals  show  notable  differences  in  hardness  in  different  direc- 
tions. Cyanite,  the  most  striking  example,  is  easily  scratched  with  a 
knife  lengthwise  on  the  broad  faces  (H  4-5),  but  crosswise  and  on  the 
thin  edges  it  is  harder  than  steel  (H  6-7). 


8  PROPERTIES  OF  MINERALS 

The  ore  minerals  of  the  heavy  metals — silver,  copper,  mercury, 
lead — are  soft,  mostly  below  3.  Sulphides,  arsenides,  and  oxides  of 
iron,  nickel,  and  cobalt  are  relatively  hard;  other  sulphides  are  mostly 
soft,  as  are  also  most  carbonates,  sulphates,  and  hydrous  minerals. 
The  very  hard  minerals  are  chiefly  oxides  and  silicates  and  many  of 
them  contain  aluminum. 

Tenacity  is  the  degree  or  character  of  cohesion.  The  distinctions 
commonly  recognized  are:  sectile,  may  be  cut  with  a  knife,  but  slices 
are  not  malleable;  malleable,  flattens  under  the  hammer;  flexible, 
may  be  bent;  elastic,  springs  back  after  bending;  brittle,  fragile, 
easily  broken,  the  opposite  of  tough;  friable,  easily  crumbled;  pul- 
verulent, powdery,  with  little  or  no  cohesion,  like  chalk  or  clay. 

Specific  gravity  is  the  weight  of  a  substance  compared  with  that 
of  an  equal  volume  of  water;  thus  a  mineral  with  specific  gravity  3 
is  three  times  as  heavy  as  water.  The  common  methods  of  determin- 
ing specific  gravity  are  based  on  the  fact  that  the  loss  in  weight  of  a 
body  immersed  in  water  is  the  weight  of  an  equal  volume  of  water. 
Thus,  if  the  weight  of  a  mineral  in  air  is  a  and  its  weight  in  water  is  w, 

sp.  gr.  =— — .    A  porous  texture,  included  or  attached  impurities, 
or  alteration  products  will  vitiate  the  result  and  may  render  it  worth- 

loca 
KSot 

Minerals  of  fixed  composition  have  a  definite  specific  gravity. 
Many  species  in  which  one  or  more  constituents  are  subject  to  iso- 
morphous  replacement,  or  substitution,  show  a  corresponding  range 
in  specific  gravity  between  certain  limits.  Whether  the  specific 
gravity  of  a  mineral  is  high,  low,  or  of  intermediate  value  may  gener- 
ally be  judged  by  the  hand  without  weighing.  Weight  per  cubic 
foot  is  obtained  by  multiplying  the  specific  gravity  by  62.5  pounds, 
the  weight  of  a  cubic  foot  of  water. 

Color  is  a  fairly  definite  and  fixed  characteristic  of  minerals  having 
metallic  luster,  but  is  very  variable  in  most  others.  In  some  it  varies 
with  isomorphous  variations  in  composition,  in  some  it  is  due  to 
minute  colored  inclusions,  while  in  others  it  is  possibly  caused  by  a 
slight  amount  of  some  substance  in  solid  solution.  In  general  the 
cause  of  color  in  minerals  is  little  understood.  Some  species  change 
or  lose  their  color  under  the  influence  of  light,  heat,  x-rays,  and  radium 
emanations;  and,  on  the  other  hand,  color  appears  under  these  in- 
fluences in  some  minerals  that  were  formerly  colorless. 

Mechanical  color  effects  include  play  or  change  of  color,  irregular 
changes  and  flashes  as  the  mineral  is  viewed  in  different  directions; 
opalescence,  a  milky  appearance,  as  in  translucent  opal;  asterism,  a 


PHYSICAL  PROPERTIES  9 

star  effect  by  reflected  or  transmitted  light,  due  to  structure  planes 
or  symmetrically  arranged  inclusions;  iridescence,  bands  of  prismatic 
colors  due  to  cracks  within  or  to  a  surface  film  produced  by  alteration 
or  deposition;  tarnish,  an  altered  surface  coating  of  different  color 
from  the  fresh  mineral. 

Streak  is  the  color  of  the  finest  powder  of  a  mineral,  or  of  the  mark 
it  will  make  on  a  harder  substance,  such  as  unglazed  porcelain,  a 
clean  whetstone,  or  a  fine-cut  file.  The  same  result  is  obtained  by 
scratching  the  mineral  in  the  test  for  hardness,  or  by  grinding  a  frag- 
ment in  a  mortar,  or  by  crushing  it  to  fine  flour  with  a  hammer  on 
clean  iron  or  steel.  The  color  of  the  streak  varies  but  little,  even  in 
those  minerals  that  show  great  color  variations  in  the  mass. 

Transparency,  or  diaphaneity. — A  mineral  is  called  transparent 
only  when  objects  can  be  seen  clearly  through  it,  translucent  if  light 
is  transmitted  but  objects  are  not  seen,  and  opaque  if  no  light  passes, 
even  through  the  thinnest  edges.  Semitransparent  and  semitranslu- 
cent  express  intermediate  degrees.  Many  minerals  that  are  com- 
monly called  opaque  are  translucent  on  thin  edges  and  transparent 
in  the  thin  sections  that  are  prepared  for  microscopic  study. 

Luster  is  the  surface  appearance  of  an  object,  or  the  manner  in 
which  it  reflects  light.  It  is  largely  dependent  on  the  character  of 
the  surface,  but  is  modified  by  the  degree  of  transparency  and  the 
refractive  index  of  the  substance.  Several  kinds  of  luster  are  com- 
monly recognized.  Metallic  is  the  luster  of  metals  and  of  some 
opaque  minerals;  submetallic  and  metalloidal  refer  to  the  same  thing 
in  subordinate  degree.  In  mineralogy  other  types  of  luster  are  often 
referred  to  collectively  as  nonmetallic,  but  the  following  varieties 
should  be  readily  recognized:  vitreous,  the  luster  of  a  broken  surface 
of  glass;  adamantine,  somewhat  like  oiled  glass — the  luster  of  the 
uncut  diamond,  zircon,  cerusite,  and  other  minerals  of  high  refrac- 
tive index;  resinous,  the  luster  of  resin  or  sphalerite.  Greasy,  oily, 
pitchy,  waxy,  pearly,  and  silky  are  self-explaining  terms.  Degrees 
of  intensity  are  designated,  in  the  order  of  decreasing  brilliance,  as 
splendent,  shining,  glistening,  glimmering.  Dull  signifies  the  absence 
of  luster,  as  in  chalk. 

Fluorescence  is  the  capacity  possessed  by  some  minerals  for 
producing  in  sunlight  or  ultraviolet  light  a  color  different  from  their 
own  and  from  that  of  the  exciting  light.  Thus  green  or  colorless 
fluorite  commonly  shows  a  bluish  or  purplish  color  in  sunlight. 

Phosphorescence  is  the  glow  induced  in  some  minerals  by  the 
action  of  moderate  heat,  friction,  mechanical  or  electrical  stress, 
ordinary  light,  ultraviolet  light,  and  radium  emanations.  The  glow 


10  PROPERTIES  OF  MINERALS 

may  continue  a  few  seconds  or  minutes  after  the  removal  of  the 
cause.  Nearly  all  specimens  of  some  minerals  (as  diamond,  willemite, 
kunzite,  sphalerite)  are  phosphorescent.  In  others  this  property 
exists  only  in  individual  specimens  or  those  from  certain  localities. 

Taste. — Some  minerals  that  are  soluble  in  water  have  a  character- 
istic taste,  which  may  be  salty,  or  saline,  the  taste  of  common  salt 
(sodium  chloride);  alkaline,  the  taste  of  soda  (sodium  bicarbonate); 
add,  or  sour,  the  taste  of  sulphuric  acid;  astringent,  the  taste  of  cop- 
peras (ferrous  sulphate) ;  sweetish  astringent,  the  taste-  of  alum  (potas- 
sium-aluminum sulphate);  cooling,  the  taste  of  niter  (potassium 
nitrate)  or  potassium  chlorate. 

Odor. — Some  minerals  yield  a  characteristic  odor  when  struck 
with  a  hammer,  rubbed,  breathed  upon,  or  heated.  These  are 
described  as  arsenical,  or  alliaceous,  like  the  odor  of  garlic  (due  to 
arsenic) ;  selenious,  or  horseradish,  the  odor  of  decaying  horseradish 
(selenium) ;  sulphurous,  the  odor  of  burning  sulphur  (sulphur) ;  fetid, 
the  odor  of  rotten  eggs  (hydrogen  sulphide) ;  argillaceous,  the  odor 
of  clay  when  breathed  upon. 

Feel  is  the  sensation  upon  touching  or  handling  minerals.  Some 
that  are  very  soft  and  greasy,  soapy,  or  unctuous  to  the  touch  are 
contrasted  with  others  that  are  notably  rough,  harsh,  or  meager. 

Magnetism  is  most  pronounced  in  magnetite,  the  only  mineral 
that  is  strongly  attracted  by  a  common  horseshoe  magnet  or  a  magnet- 
ized knife  blade,  which  will  pick  up  grains  the  size  of  a  pea  or  larger. 
Pyrrhotite,  or  magnetic  pyrites,  and  native  platinum  (alloyed  with 
iron)  are  also  commonly  magnetic,  and  many  specimens  of  hematite, 
ilmenite,  chromite,  and  franklinite  are  weakly  so  and  are  attracted 
in  minute  particles.  All  iron-bearing  minerals,  even  silicates  with 
small  percentages  of  iron,  respond  to  powerful  electromagnets.  Mag- 
netite that  possesses  attracting  power  and  polarity  is  called  loadstone, 
or  natural  magnet. 

Pyroelectricity  is  the  capacity  for  developing  electric  charges 
at  opposite  ends  or  other  parts  of  a  crystal  or  crystalline  frag- 
ment when  gently  heated.  This  property  is  most  notable  in  hemi- 
morphic  minerals,  such  as  tourmaline  and  calamine  (electric 
calamine).  The  poles  will  attract  minute  bits  of  paper  and  other 
very  light  objects, 

CHEMICAL  PROPERTIES 

Composition. — Minerals  are  either  uncombined  elements,  such  as 
native  gold  (Au),  copper  (Cu),  sulphur  (S),  or  definite  compounds  of 


CHEMICAL  PROPERTIES  11 

the  elements,  as  quartz  (Si02),  calcite  (CaCOs),  gypsum  (CaSCV 
2H20).  Chemical  composition  is  the  most  fundamental  property  of 
minerals,  and  for  purposes  of  description  they  are  commonly  classi- 
fied on  this  basis.  Thus  the  native  elements  are  grouped  together, 
and  likewise  the  sulphides,  oxides,  carbonates,  silicates,  phosphates, 
etc.  In  determinative  tables,  such  as  appear  in  this  book,  the  object 
is  to  group  them  according  to  such  physical  or  chemical  characters 
as  will  most  facilitate  the  identification  of  unknown  specimens. 

Chemical  analyses  of  minerals  often  vary  from  the  formulas  by 
which  they  are  represented  on  account  of  one  or  more  of  the  following 
causes:  (1)  Isomorphism  (see  below);  (2)  solid  solution  (e.g.,  pyr- 
rhotite  with  excess  S) ;  (3)  alteration  or  decomposition:  (4)  inclu- 
sion of  crystals  or  particles  of  another  mineral;  (5)  other  minerals 
attached  to  the  specimen  or  particles  mixed  in  an  aggregate,  as 
gangue  minerals  in  an  ore. 

Isomorphism  is  the  capacity  possessed  by  some  minerals  of  anal- 
ogous composition  and  similar  crystal  form  of  uniting  in  variable 
proportions  to  form  homogeneous  mixed  crystals.  In  the  group 
of  the  rhombohedral  carbonate  minerals,  for  example,  calcite,  which 
is  essentially  CaCOs,  may  also  contain  more  or  less  magnesite,  MgCOs, 
siderite,  FeCOs,  and  rhodochrosite,  MnCOs.  This  mingling  of 
isomorphous  minerals  in  the  same  crystal  is  equivalent  to  the  sub- 
stitution of  magnesium,  iron,  and  manganese  for  a  part  of  the  cal- 
cium in  calcite,  and  may  be  expressed  in  the  chemical  formula  thus: 
(Ca,  Mg,  Fe,  Mn)COa.  Salts  of  different  acids  may  also  be  isomor- 
phous, as  in  the  apatite  group,  which  includes  phosphates,  arsenates, 
and  vanadates.  Most  minerals  are  isomorphous  mixtures  and  con- 
sequently subject,  within  limits,  to  variations  in  composition,  specific 
gravity,  color,  and  other  properties,  corresponding  to  the  varying 
proportions  of  the  interchangeable  constituents. 

Polymorphism,  or  pleomorphism,  is  the  occurrence  of  two  or 
more  minerals  of  the  same  composition  but  differing  in  crystalliza- 
tion and  in  physical  and  optical  properties.  In  some  cases  there  are 
also  pronounced  differences  in  chemical  properties.  Native  carbon 
is  dimorphous,  occurring  as  graphite  and  diamond;  titanium  dioxide 
forms  the  three  minerals,  rutile,  brookite,  and  octahedrite,  and  hence 
is  said  to  be  trimorphous.  Allotropy  and  isomerism  are  chemical 
terms  with  somewhat  similar  meaning;  thus  there  are  four  allotropic 
forms  of  sulphur;  the  butyl  alcohols  and  ordinary  ether  are  isomeric. 


IDENTIFICATION  OF  MINERALS  BY  MEANS  OF  THEIR 
PHYSICAL  PROPERTIES 

Preliminary  Instructions  and  Precautions 

If  the  crystal  system  can  be  determined,  either  from  crystals  or 
from  cleavage,  the  crystal  tables,  pages  266  to  274,  will  often  prove 
the  most  convenient  means  of  identification. 

Physical  properties  can  be  accurately  determined  only  from  fresh, 
homogeneous  material,  preferably  crystalline.  If  the  specimen  is 
tarnished  or  decomposed  at  the  surface  a  fresh  fracture  will  often 
disclose  unaltered  material  within. 

Hardness  of  a  mineral  is  estimated  by  comparison  with  a  sub- 
stance that  is  just  hard  enough  to  scratch  it,  remembering  that  sub- 
stances of  the  same  hardness  will  scratch  each  other  slightly.  Press 
a  point  or  edge  of  known  hardness  against  a  smooth  surface  of  the 
mineral  and  move  it  back  and  forth  in  the  same  line  about  one-eighth 
of  an  inch  (3  mm.).  Select  an  inconspicuous  place  and  do  not 
scratch  the  specimen  more  than  necessary. 

A  "  chalk  "  mark  must  not  be  mistaken  for  a  true  scratch.  Brush 
away  the  powder  and  examine  the  smooth  surface  of  the  mineral. 
Rough  or  altered  surfaces  do  not  give  reliable  results.  Alteration 
products  are  generally  softer  than  the  original  mineral. 

Powdery,  earthy,  and  fibrous  minerals  generally  appear  to  be 
both  softer  and  lighter  than  they  really  are.  On  the  other  hand 
a  soft  mineral  may  appear  harder  than  it  really  is  on  account  of 
attached  or  intermingled  grains  of  quartz  or  other  hard  substance. 

A  crystal  or  other  mineral  specimen  should  not  be  separated 
entirely  from  the  matrix  in  which  it  is  imbedded  or  the  rock  or 
mineral  aggregate  to  which  it  is  attached.  Mode  of  occurrence  and 
mineral  associates  are  important  aids  to  identification  and  shed  much 
light  on  questions  of  origin. 

Avoid  breaking  any  specimen  if  there  are  enough  fragments 
for  tests.  When  it  is  necessary  to  break  it,  hold  the  specimen  firmly 
in  the  hand,  so  as  to  catch  the  fragments  in  the  palm,  and  strike  a 
quick,  sharp  blow  with  a  light  hammer  on  a  projecting  edge  or  corner 
near  the  under  surface.  Do  not  break  nor  otherwise  injure  a  good 
crystal,  if  it  is  possible  to  avoid  it. 

12 


GENERAL  CLASSIFICATION 

(For  abbreviations  used  in  the  tables,  see  page  285.) 

Streak  black  or  nearly  so:                                             SECTION  PAQB 

Mineral  silver-white  to  steel-gray 1  14 

Mineral  dark  gray,  black,  blue,  or  green 2  17 

Mineral  yellow,  red,  or  brown 3  23 

Streak  silver-white  to  steel  gray 4  26 

Streak  chalk-white,  colorless,  or  pale  colored: 

Mineral  white,  colorless,  or  pale  colored: 

Distinct  cleavage  in  one  direction  only 5  29 

Distinct  cleavage  in  two  directions 6  34 

Distinct  cleavage  in  three  or  more  directions .       7  39 

No  distinct  cleavage l 8  46 

Mineral  dark  gray  to  black: 

Distinct  cleavage  in  one  direction  only 9  57 

Distinct  cleavage  in  two  directions 10  61 

Distinct  cleavage  in  three  or  more  directions .     11  64 

No  distinct  cleavage  l 12  69 

Mineral  yellow,  red,  or  brown: 

Distinct  cleavage  in  one  direction  only 13  75 

Distinct  cleavage  in  two  directions 14  80 

Distinct  cleavage  in  three  or  more  directions .      15  85 

No  distinct  cleavage 1 16  92 

Mineral  green,  blue,  or  violet: 

Distinct  cleavage  in  one  direction  only 17  104 

Distinct  cleavage  in  two  directions 18  109 

Distinct  cleavage  in  three  or  more  directions  .19  114 

No  distinct  cleavage 1 20  119 

Streak  yellow,  red,  or  brown: 

Mineral  black  or  nearly  so 21  128 

Mineral  yellow,  red,  or  brown 22  135 

Streak  blue  or  green 23  145 

1  In  specimens  with  fine  granular,  fibrous,  or  dense  texture,  it  may  be  impos- 
sible to  determine  whether  or  not  the  mineral  has  cleavage.  Hence,  if  not  found 
in  this  section  of  the  tables,  specimens  of  this  character  should  be  sought  in  the 
three  preceding  sections,  disregarding  altogether  the  question  of  cleavage. 

13 


SECTION  1 

Streak  black  or  nearly  so;  mineral  silver- white  to  steel-gray. 
H. 

1|    G.  7.9-8.3    SYLVANITE   AuAgTe*;    Au  24.5%;     Ag  13.4%. 
2          Struct. — Branching  aggregates,  some  like  ancient  script  (graphic  tellurium) ; 
bladed,  columnar,  granular;    monoclinic  crystals  rare.     Cleavage  distinct  one 
direction  (010)',   brittle;    fracture  uneven. 

Color  silver-white  to  steel-gray,  sometimes  brassy  tinge.  Streak  whitish, 
steel-gray.  Luster  metallic.  Opaque.  (See  p.  206.) 

In  veins  with  gold,  calaverite,  sphalerite,  pyrite,  tetrahedrite. 

2      G.  6.4-6.5     Bismuthinite  (Bismuthine,  Bismuth  Glance),  Bi2S3;   Bi  81.2%. 

Struct. — Granular,  foliated,  fibrous;  slender  orthorhombic  crystals  rare. 
Cleavage  perfect  one  direction  lengthwise  (010) ;  slightly  sectile. 

Color  light  lead-gray,  often  yellowish  tarnish.  Streak  dark  lead-gray. 
Luster  metallic.  Opaque.  (See  p.  202.) 

In  veins  with  bismuth,  chalcopyrite,  cassiterite,  gersdorffite,  wolframite. 

2  G.  5.5-6.0    JAMESONITE  (Feather  Ore),  Pb2Sb2S5;  Pb  50.8%;   often  some  Fe. 

3  Struct. — Acicular  othorhombic  crystals;   fibrous,  felted,  compact;   feath- 
ery appearance  common.     Cleavage  distinct,  one  direction  crosswise    (001); 
brittle;  fracture  uneven. 

Color  steel-gray  to  dark  lead-gray.  Streak  grayish  black.  Luster  metallic. 
Opaque.  (See  p.  198.) 

In  veins  with  bournonite,  galena,  sphalerite,  stibnite. 

2|    G.  8.3-8.4    KRENNERITE,  AuAgTe4;  Au  24.5%;  Ag  13.4%. 

Struct. — Small  prismatic  orthorhombic  crystals  striated  lengthwise. 
Cleavage  distinct  crosswise  (001);  brittle;  fracture  uneven. 

Color  silver-white  to  brass-yellow.  Streak  steel-gray.  Luster  metallic. 
Opaque.  (See  p.  206.) 

In  veins  with  sylvanite,  calaverite,  molybdenite,  pyrite,  fluorite. 

2|    G.  8.3-8.5    HESSITE,  AgzTe;  Ag  63.3%;  often  some  Au. 
3         Struct. — Fine  grained  to  compact;    isometric  crystals  rare.     Cleavage 
none;   somewhat  sectile;   fracture  uneven. 

Color  steel-gray  to  lead-gray.  Streak  gray.  Luster  metallic.  Opaque. 
(See  p.  206.) 

In  veins  with  other  tellurides,  pyrite,  chalcopyrite,  fluorite. 

21     G.  8.7-9.0    PETZITE,  Ag3AuTe2;  Ag  42%;  Au  25.5%. 
3          Struct. — Granular,  compact.     Cleavage  none;    slightly  sectile  to  brittle; 
fracture  uneven. 

Color  steel-gray  to  iron-black.  Streak  steel-gray.  Luster  metallic. 
Opaque.  (See  p.  206.) 

In  veins  with  hessite,  calaverite,  altaite,  pyrite,  siderite,  quartz,  gold. 
14 


SEC.  1]  PHYSICAL  TABLES  15 

H. 

3  G.  8.1-8.2    Altaite,  PbTe;  Pb  62.3%;  some  Ag  and  Au. 

Struct.  —  Compact;  rarely  isometric  crystals.  Cleavage  three  directions 
at  90°  (100);  sectile;  fracture  uneven. 

Color  tin-white,  yellowish;  tarnish  bronze-yellow.  Streak  gray.  Luster 
metallic.  Opaque.  (See  p.  206.) 

In  veins  with  other  tellurides,  native  tellurium,  pyrite,  galena,  tetrahedrite. 

4  G.  4.3-4.5    Stannile   (Stannine,    Tin   Pyrites,   Bellmetal  Ore),   Cu2FeSnS4; 

Sn  27.5%;  Cu  29.5%;  also  Zn  replacing  iron  up  to  10%. 

Struct.  —  Compact,  granular,  disseminated;  small  tetragonal  crystals  rare. 
Cleavage  indistinct;  brittle;  fracture  uneven. 

Color  steel-gray  to  iron-black;  tarnish  bluish;  may  be  yellow  from  ad- 
mixture of  chalcopyrite.  Streak  black.  Luster  metallic.  Opaque.  (See 
p.  200.) 

In  veins  with  quartz,  pyrite,  scheelite,  chalcopyrite,  gold,  silver,  galena, 
sphalerite. 

5  G.  7.0-7.4     LdUingite,  FeAsa,  passing  into  Fe3As4  (Leucopyrite)  . 

5%  Struct.  —  Granular,  compact;  orthorhombic  crystals  rare.  Cleavage 
indistinct,  one  direction  (001);  brittle;  fracture  uneven. 

Color  silver-white  to  steel-gray;  tarnish  gray.  Streak  grayish  black. 
Luster  metallic.  Opaque.  (See  p.  196.) 

With  arsenopyrite,  siderite,  cassiterite,  hornblende,  serpentine. 

5£     G.  6.0-6.3    COBALTITE   (Cobalt  Glance),   CoAsS;    Co  35.5%;    As  45.2%; 

some  Fe. 

Struct.  —  Isometric  crystals  (cubes,  pyritohedrons,  Figs.  5,  18,  20); 
granular,  compact.  Cleavage  indistinct,  three  directions  at  90°  (100); 
brittle;  fracture  uneven. 

Color  silver-white  to  gray,  sometimes  reddish.  Streak  grayish  black. 
Luster  metallic.  Opaque.  (See  p.  196.) 

With  silver,  smaltite,  niccolite,  pyrrhotite,  chalcopyrite;  often  with  pink 
coating  of  erythrite. 


5|    G.  4.8-5.0    LINNAEITE  (Cobalt  Pyrites)  (Ni,Co)3S4;  Ni  12-43%; 

Struct.  —  Isometric  crystals,  commonly  octahedrons  (Fig.  1);  granular. 
Cleavage  indistinct,  three  directions  at  90°  (100);  brittle;  fracture  uneven. 

Color  pale  steel-gray,  tarnish  copper-red.  Streak  grayish  black.  Luster 
metallic.  Opaque.  (See  p.  202.) 

In  veins  with  chalcopyrite,  pyrrhotite,  siderite,  cobalt  and  nickel  minerals. 

5^     G.  5.6-6.2    GERSDORFFITE,  NiAsS;   Ni  35.4%;   often  much  Fe. 

Struct.  —  Granular,  lamellar;  isometric-pyritohedral  crystals.  Cleavage 
indistinct,  three  directions  at  90°  (100);  brittle;  fracture  uneven. 

Color  tin-white  to  steel-gray.  Streak  grayish  black.  Luster  metallic. 
Opaque.  (See  p.  196.) 

With  ores  of  cobalt,  nickel,  silver,  and  copper. 


16  DETERMINATIVE  MINERALOGY  [SEC.  1 

H. 

51  G.  5.9-6.2  ARSENOPYRITE  (Arsenical  Pyrites,  Mispickel),  FeAsS;  As 
6  46%. 

Struct. — Granular,  compact;  orthorhombic  crystals,  like  marcasite. 
Cleavage  indistinct,  two  directions  at  68°  and  112°  (110);  brittle;  fracture 
uneven. 

Color  silver-white  to  steel-gray.  Streak  grayish  black.  Luster  metallic. 
Opaque.  (See  p.  196.) 

With  ores  of  gold,  silver,  lead,  tin;  with  pyrite,  chalcopyrite,  sphalerite, 
smaltite.  , 

51    G.  6.4-6.6    SMALTITE,  CoAs2;  Co  28.2%;  some  Ni  and  Fe. 
6          Struct. — Granular,  compact;  isometric-pyritohedral  crystals  rare.     Cleav- 
age indistinct,  four  directions  at  70|°  and  109^°  (111);    brittle;    fracture 
uneven. 

Color  tin-white  to  steel-gray;   often  grayish  tarnish  and  pink  coating  of 
erythrite.     Streak  grayish  black.     Luster  metallic.     Opaque.     (See  p.  196.) 
With  niccolite,  cobaltite,  native  bismuth  and  silver,  proustite,   barite, 
fluorite,  calcite. 

5£    G.  6.4-6.6    CHLOANTHITE,  NiAs2;  Ni28.1%;  some  Co  and  Fe. 
6          Struct. — Granular,  compact;  isometric-pyritohedral  crystals  rare.     Cleav- 
age indistinct,  four  directions  at  70J  and  109^°  (111);   brittle;   fracture  un- 
even. 

Color  tin-white  to  steel-gray;  often  grayish  tarnish  and  green  coating  of 
annabergite.  Streak  grayish  black.  Luster  metallic.  Opaque.  (See  p. 
196.) 

With  niccolite,  cobaltite,  proustite,  native  silver  and  bismuth,  fluorite, 
barite,  calcite. 

6  G.  4.8-4.9  MARCASITE  (White  Iron  Pyrites,  White  Iron),  FeS2;  Fe 
6£  46.6%;  S53.4%. 

Struct. — Tabular  orthorhombic  crystals  and  twin  groups,  often  cocks- 
comb or  spear-head  forms  (cockscomb  pyrites,  spearhead  pyrites);  compact, 
stalactitic,  rounded  concretions.  Cleavage  indistinct,  two  directions  at  75° 
and  105°  (110);  brittle;  fracture  uneven. 

Color  pale  brass-yellow  to  almost  white,  tarnish  deeper  yellow  to  brown. 
Streak  dark  greenish  to  brownish  black.  Luster  metallic.  Opaque.  (See 
p.  200.) 

Alters  readily  on  exposure  to  capillary  melanterite  and  to  limonite;  much 
less  stable  than  pyrite.  With  lead  and  zinc  ores,  pyrite,  chalcopyrite,  cinna- 
bar; concretions  in  clay,  shale,  and  coal. 

6      G.  4.7-4.8    Braunite,  3Mn2O3.MnSiO3;  Mn  64.4%. 

6J  Struct. — Granular;  drusy  crusts;  minute  tetragonal  crystals,  resembling 
octahedrons.  Cleavage  distinct,  four  directions  at  70°  and  110°  (111); 
brittle;  fracture  uneven. 

Color  brownish  black  to  steel-gray.     Streak  black,  brownish  black. 
Luster  submetallic,  greasy.     Opaque.     (See  p.  208.) 

With  manganese  minerals,  magnetite,  hematite,  barite. 


SEC.  2]  PHYSICAL  TABLES  17 

SECTION  2 

Streak  black  or  nearly  so;  mineral  dark  gray,  black,  blue,  or  green. 
H. 

0  CHALCOCITE,  MELACONITE,  ARGENTITE,  PYROLUSITE,  WAD. 

1  Black,  powdery,  earthy.     (See  pp.  17,  18,  19,  21.) 

1      G.  4.7-4.8    MOLYBDENITE,  MoS*;  Mo  60.0%. 

li  Struct. — Scales,  foliated  masses,  grains;  tabular  hexagonal  crystals  rare. 
Cleavage  perfect,  one  direction  (0001);  thin  flakes  flexible;  sectile;  feels 
greasy. 

Color  bluish  lead-gray.  Streak  grayish  black,  greenish  on  glazed  paper 
or  porcelain.  Luster  metallic.  Opaque.  (See  p.  210.) 

In  granite,  pegmatite,  syenite,  gneiss,  with  cassiterite,  pyrrhotite,  wol- 
framite, tourmaline,  topaz;  in  crystalline  limestone  with  epidote,  chalcopy- 
rite;  in  crystalline  schists;  in  basic  igneous  rocks. 

1  G.  1.9-2.3     GRAPHITE   (Black  Leak,  Plumbago),  C;    often  Fe,  clay,  etc. 

2  Struct. — Foliated,   scaly,   granular,   earthy;    tabular  hexagonal   crystals 
rare.     Cleavage    perfect,  one  direction  (0001);   thin  flakes  flexible;    sectile; 
feels  greasy. 

Color  steel-gray  to  iron-black.  Streak  grayish  black,  shiny  Luster 
metallic.  Opaque.  (See  p.  210.) 

In  gneiss  and  mica  schist;  in  crystalline  limestone  with  garnet,  spinel, 
wollastonite,  pyroxene,  amphibole. 

1      G.  1.0-1.8    ASPHALT  (Asphaltum,  Mineral  Pitch),  C,  H,  O,  etc. 

3  Struct. — Amorphous;     solid    or    very    viscous    liquid.     Cleavage  none; 
brittle  to  flexible;  fracture  conchoidal. 

Color  black  to  brownish  black.  Streak  brownish  black.  Luster  pitchy, 
resinous,  dull.  Opaque.  Bituminous  odor;  sticky  when  plastic.  (Seep.  212). 

Massive  deposits  ("  pitch  lakes,"  etc.)  and  impregnating  sedimentary 
strata. 

1  G.  3.0-4.3     WAD  (Bog  Manganese),  MnO2,  H2O;  often  Fe,  Si,  Al,  Ba,  Co. 
3          Mn  up  to  60%.     Asbolan  (Earthy  Cobalt)  contains  Co  to  25%. 

Struct. — Earthy,  porous  (floating)  to  compact;  sometimes  globular; 
amorphous.  Cleavage  none;  brittle;  fracture  earthy. 

Color  bluish  or  brownish  black  to  dull  black.  Streak  brownish  black  to 
black.  Luster  metallic  to  dull.  Opaque.  (See  pp.  208,  250.) 

In  residual  soil,  clay,  and  swamp  deposits,  with  psilomelane,  pyrolusite, 
siderite,  limonite. 

1|    G.  4.6  COVELLITE  (Covettine,  Indigo  Copper),  CuS;  Cu  66.4%. 

2  Struct. — Disseminated,   compact,  in  crusts;    tabular  hexagonal  crystals 
rare.     Cleavage  perfect,  one  direction  (0001);    thin  laminae  flexible;    brittle 
in  mass;    fracture  uneven. 

Color  dark  indigo-blue.  Streak  lead-gray  to  black.  Luster  submetallic, 
resinous,  dull.  Opaque.  (See  p.  200.) 

In  copper  ores  with  bornite,  chalcocite,  chalcopyrite. 


18  DETERMINATIVE  MINERALOGY  [Ssc.  2 

H. 

2      G.  4.5-4.6    STIBNITE   (Antimonite,   Antimony  Glance,    Gray   Antimony) 

Sb2S3;    Sb71.8%. 

Struct. — Long  prismatic  orthorhombic  crystals,  often  bent  or  twisted; 
columnar,  bladed,  granular.  Cleavage  perfect,  one  direction  lengthwise  (010); 
crystals  striated  lengthwise;  brittle,  slightly  sectile;  fracture  uneven;  crys- 
tals slightly  flexible. 

Color  lead-gray;  tarnish  black,  sometimes  iridescent.  Streak  dark  lead- 
gray.  Luster  metallic.  Opaque.  (See  p.  198.) 

In  quartz  veins  in  granite  and  gneiss  with  pyrite,  sphalerite,  galena,  barite, 
cinnabar,  realgar. 

2      G.  6.4-6.5     Bismuthinite  (Bismuthine,  Bismuth  Glance),  Bi2S3;  Bi  81.2%. 

Struct. — Granular,  foliated,  fibrous;  slender  orthorhombic  crystals  rare. 
Cleavage  perfect,  one  direction  lengthwise  (010);  slightly  sectile. 

Color  light  lead-gray;  often  yellowish  tarnish.  Streak  dark  lead-gray. 
Luster  metallic.  Opaque.  (See  p.  202.) 

In  veins  with  bismuth,  chalcopyrite,  cassiterite,  gersdorffite,  wolframite. 

2      G.  4.7-4.8    PYROLUSITE,  MnO2;  commonly  a  little  H2O;   Mn  63.2%. 
2%        Struct. — Columnar,  acicular,  fibrous,  radial,  dendritic,  powdery;   crystals 
pseudomorphous  after  manganite  (orthorhombic).     Cleavage  none;  brittle; 
fracture  splintery,  uneven. 

Color  black  to  steel-gray.  Streak  black,  bluish  black.  Luster  metallic, 
dull.  Opaque.  (See  p.  208.) 

In  residual  clays  of  limestone  and  slate  with  manganite,  psilomelane, 
hematite,  limonite,  barite;  dendritic  in  joint  cracks. 

2      G.  7:2-7 A    ARGENTITE  (Silver  Glance),  AgaS;  Ag  87.1%. 
2  \        Struct. — Compact;    disseminated,   in  crusting;    rough  isometric   crystals 
rare,  often  distorted.     Cleavage  indistinct;    perfectly  sectile,  cuts  like  lead; 
fracture  hackly. 

Color  lead-gray  to  black.  Streak  dark  lead-gray,  shiny.  Luster  metallic. 
Opaque.  (See  p.  200.) 

In  veins  with  silver,  ruby  silvers,  stephanite,  galena,  smaltite,  niccolite. 

2      G.  6.2-6.3    STEPHANITE  (Brittle  Silver,  Black  Silver),  Ag6SbS4;   Ag  68.5%. 
2\        Struct. — Disseminated,  compact;  tabular  or  thick  prismatic  orthorhombic 
crystals,    often    pseudohexagonal.     Cleavage    imperfect;     brittle;     fracture 
uneven. 

Color  dark  lead-gray  to  iron-black.  Streak  iron-black.  Luster  metallic. 
Opaque.  (See  p.  198.) 

In  veins  with  other  silver  minerals,  galena,  barite. 

2      G.  1.1-1.4    LIGNITE  (Brown  Coal),  C,  H,  O,  etc.;    C  65-76%;    "fixed" 
J8J  C  30-60%. 

Struct. — Compact,  amorphous;  woody  structure  common.  Cleavage 
none;  fracture  conchoidal,  splintery;  may  crumble  on  exposure. 

Color  brownish  black  to  black.  Streak  brown  to  brownish  black.  Luster 
dull;  resinous  (jet).  Opaque.  Burns  with  a  smoky  yellow  flame.  (See  p.  212.) 


SEC.  2]  PHYSICAL  TABLES  19 

H. 

Plant  remains  commonly  recognizable.  Jet  is  a  black  compact  variety 
that  takes  a  polish.  In  stratified  rocks,  sands,  clays,  with  pyrite  and  mar- 
casite. 

2      G.  1.2-1.5    BITUMINOUS  COAL  (Soft  Coal),  C,  H,  O,  etc.;  C  76-88%;  "fixed" 
2\  C  48-73%. 

Struct. — Amorphous;  compact,  lamellar,  rarely  fibrous.  Cleavage  none; 
brittle;  cubical  fracture  conspicuous,  sometimes  conchoidal. 

Color  and  streak  black  to  brownish  black.  Luster  pitchy,  vitreous,  dull. 
Opaque.  Burns  with  a  smoky  yellow  flame.  (See  p.  212.) 

Sometimes  shows  plant  remains;  sometimes  iridescent.  Coking  coal 
becomes  pasty  in  the  fire.  Cannel  coal  is  dull  black,  compact,  structureless, 
with  conchoidal  fracture.  Beds  in  stratified  rocks,  with  pyrite  and  marcasite. 

2      G.  1.3-1.7    ANTHRACITE    COAL  (Hard  Coal),  C  85-95%;     volatile  1-5%. 
2 \         Struct. — Amorphous,   compact.     Cleavage  none;    very  brittle;    fracture 
conchoidal. 

Color  iron-black  to  black,  often  iridescent.     Streak  black.     Luster  vitre- 
ous, submetallic.     Opaque.     Burns  with  pale  feeble  flame.     (See  p.  212.) 
Beds  in  stratified  rocks,  with  pyrite  and  marcasite. 

2  G.  6.0-6.2     POLYBASITE,  (Ag,Cu)9SbS6;    Ag  62-72%;     Cu  3-10%;   some- 

3  times  As. 

Struct. — Tabular  six-sided  monoclinic  crystals  with  triangular  markings 
on  base;  compact,  disseminated.  Cleavage  imperfect,  one  direction  (001); 
brittle;  fracture  uneven. 

Color  iron-black;  in  thin  splinters  cherry-red.  Streak  black.  Luster 
metallic.  Nearly  opaque.  (See  p.  198.) 

In  veins  with  other  silver  minerals,  galena,  sphalerite;  replacements  in 
limestone. 

2  G.  5.5-6.0    JAMESONITE  (Feather  Ore),  Pb2Sb2S5;  Pb  50.8%;  often  some  Fe. 

3  Struct. — Acicular  orthorhombic  crystals;   fibrous,  felted,  compact;   feath- 
ery appearance  common.     Cleavage  distinct,  one  direction  crosswise  (001); 
brittle;   fracture  uneven. 

Color  steel-gray  to  dark  lead-gray.  Streak  grayish  black.  Luster  metal- 
lic. Opaque.  (See  p.  198.) 

In  veins  with  bournonite,  galena,  sphalerite,  stibnite. 

3|    G.  7.4-7.6    GALENA  (Galenite,  Lead  Glance),  PbS;    Pb  86.6%;    often  Ag. 
Struct. — Cleavable  masses,  granular,  compact;    isometric  crystals  (com- 
monly cubes,  Fig.  5).     Cleavage  perfect,  three  directions  at  90°  (100);  brittle. 
Color  and  streak  dark  lead-gray.    Luster  metallic.    Opaque.  (See  p.  200.) 
In  ore  deposits  with  sphalerite,  pyrite,  chalcopyrite,  barite,  fluorite,  calcite. 

2|     G.  5.5-5.8    CHALCOCITE  (Copper  Glance,  Redruthite),  Cu2S;   Cu  79.8%; 
3  sometimes  Fe. 

Struct. — Granular   compact,    disseminated;    rarely   in   pseudohexagonal 

orthorhombic  crystals,  deeply  striated.     Cleavage  indistinct;   rather  brittle; 

fracture  conchoidal. 


20  DETERMINATIVE  MINERALOGY  [Sfic.  2 


Color  dark  lead-gray;  tarnish  dull  black,  blue,  or  green.  May  be  coated 
with  malachite  (green)  or  azurite  (blue).  Streak  dark  gray  to  black,  shiny. 
Luster  metallic.  Opaque.  (See  p.  200.) 

In  veins  with  pyrite,  chalcopyrite,  bornite,  tetrahedrite,  hematite,  galena. 

2|    G.  5.7-5.9    BOURNONITE  (Cogwheel  Ore,  Wheel  Ore,  Enddlionite),  PbCuSbS3; 
3  Pb42.5%;  Cu  13%. 

Struct. — Fine  grained,  compact;  thick  tabular  orthorhombic  crystals  or 
cross  "  cogwheel  "  twins.  Cleavage  indistinct;  brittle;  fracture  uneven. 

Color  steel-gray  to  iron-black.  Streak  dark  gray  to  black.  Luster  metal- 
lic. Opaque.  (See  p.  198.) 

In  veins  with  galena,  sphalerite,  tetrahedrite,  siderite,  stibnite,  chalcocite. 

3|    G.  6.2-6.3    STROKE YERITE,  AgCuS;  Ag  53.1%;  Cu31.1%. 
3          Struct. — Compact;    rarely  twinned  pseudohexagonal  orthorhombic  crys- 
tals.    Cleavage  none;  slightly  sectile;  fracture  subconchoidal,  uneven. 

Color  dark  lead-gray.  Streak  dark  lead-gray  to  black.  Luster  metallic. 
Opaque.  (See  p.  200.) 

In  veins  with  copper  and  silver  ores,  argentite,  proustite,  chalcocite, 
tetrahedrite. 

2%    G.  8.3-8.5    HESSITE,  Ag2Te;  Ag  63.3%;  often  some  Au. 
3          Struct. — Fine  grained  to   compact;    isometric  crystals  rare.     Cleavage 
none;   somewhat  sectile;  fracture  uneven. 

Color  steel-gray  to  lead-gray.  Streak  gray.  Luster  metallic.  Opaque. 
(See  p.  206.) 

In  veins  with  other  tellurides,  pyrite,  chalcopyrite,  fluorite. 

3|    G.  8.7-9.0    PETZITE,  Ag3AuTe2;  Ag  42%;  Au  25.5%. 
3          Struct. — Granular,  compact.     Cleavage  none;    slightly  sectile  to  brittle; 
fracture  uneven. 

Color  steel-gray  to  iron-black.  Streak  steel-gray.  Luster  metallic. 
Opaque.  (See  p.  206.) 

In  veins  with  hessite,  calaverite,  altaite,  pyrite,  siderite,  quartz,  gold. 

3      G.  4.4-4.5    ENARGITE,  Cu3AsS4;   Cu  48.3%;   As  19.1%;   some  Sb. 

Struct. — Compact,    columnar,    granular;    small   prismatic   orthorhombic 

crystals  rare.     Cleavage  distinct,  two  directions  lengthwise  (110)  at  82°  and 

98°;  brittle;  fracture  uneven. 

Color  and  streak  grayish  black.    Luster  metallic.    Opaque.    (See  p.  196.) 
In  veins  with  pyrite,  chalcopyrite,  bornite,  chalcocite,  tennantite. 

3      G.  6.1-6.2    PEARCEITE,  (Ag,Cu)9AsS6;  Ag  55-60%. 

Struct. — Tabular  six-sided  monoclinic  crystals  with  triangular  markings 

on  the  base;   compact,  disseminated.     Cleavage  none;  brittle;  fracture  con- 

choidal. 

Color  and  streak  black.     Luster  metallic.     Opaque.     (See  p.  196.) 
In  silver  ores  with  galena,  chalcopyrite,  quartz,  calcite,  siderite,  barite. 


SEC.  2]  PHYSICAL  TABLES  21 

H. 

3  G.  4.4-5.1    TETRAHEDRITE  (Gray  Copper),  CujSbSs;    often  some  Fe, 

4  Zn,  Pb,  Ag,  As.     Cu  46.8%;    Freibergite  has  Ag  3-15%. 
With  increasing  As  grades  into  Tennantite,  CuaAsSa. 

Struct. — Isometric-tetrahedral  crystals  (Figs.  13,  14,  17);  granular,  com- 
pact. Cleavage  none;  brittle;  fracture  uneven. 

Color  steel-gray  to  iron-black.  Sometimes  coated  with  brass-yellow 
chalcopyrite.  Streak  dark  gray,  black,  reddish  brown.  Luster  metallic. 
Opaque.  (See  p.  198.) 

In  veins  with  silver,  lead,  and  copper  ores, 

3  G.  5.8-6.2     MELACONITE  (Tenorite,  Black  Copper,  Black  Oxide  of  Copper), 

4  CuO;  Cu  79.8%. 

Struct. — Earthy  massive  and  powder  (melaconite) .  Thin  scaly  pseudohex- 
agonal  monoclinic  crystals  (tenorite)  rare;  Cleavage  indistinct;  crystals 
brittle;  fracture  uneven. 

Color  steel-gray  to  black.  Streak  black.  Earthy  varieties  soil  the  fingers. 
Luster  metallic;  dull.  Opaque.  (See  p.  204.) 

Black  coatings  and  crusts  on  native  copper  and  various  copper  minerals. 

3  G.  3.0-4.3    WAD  (Bog  Manganese),  MnO2,  H2O;  often  Fe,  Si,  Al,  Ba,  Co. 

4  Black,  compact;  H  1-6.     (See  p.  17.) 

3|    G.  4.2-4.4    MANGANITE,  MnO -OH;  Mn  62.4%;  H2O  10.3%. 
4          Struct. — Prismatic  orthorhombic  crystals  striated  lengthwise;  often  groups 
or  bundles.     Cleavage  perfect,  one  direction  lengthwise  (010) ;  rarely  granular, 
stalactitic;  brittle;  fracture  uneven. 

Color  steel-gray  to  iron-black.  Streak  reddish  brown  to  black.  Luster 
metallic,  submetallic.  Opaque.  (See  p.  208.) 

Often  altered  to  pyrolusite.  With  ores  of  manganese  and  iron;  barite, 
calcite,  siderite. 

4  G.  4.3-4.5    Stannite   (Stannine,    Tin   Pyrites,   Bellmetal  Ore),   Cu2FeSnS4; 

Sn  27.5%;  Cu  29.5%;  also  Zn  replacing  iron  up  to  10%. 

Struct. — Compact,  granular,  disseminated;  small  tetragonal  crystals  rare. 
Cleavage  indistinct;  brittle;  fracture  uneven. 

Color  steel-gray  to  iron-black;  may  be  yellow  from  admixture  of  chal- 
copyrite; tarnish  bluish.  Streak  black.  Luster  metallic.  Opaque.  (See 
p.  200.) 

In  veins  with  quartz,  pyrite,  scheelite,  chalcopyrite,  gold,  silver,  galena, 
sphalerite. 

5  G.  7.2-7.5    WOLFRAMITE    (Wolfram),  (Fe,Mn)WO4;     grades  into  Fer- 
5$  berite,  FeWO4,  and  Huebnerite,  MnWO4;  WO3  about  76%. 

Struct. — Thick  tabular,  short  columnar,  and  bladed  monoclinic  crystals, 
resembling  orthorhombic;  cleavable,  granular,  compact.  Cleavage  perfect, 
one  direction  (010);  brittle;  fracture  uneven. 


22  DETERMINATIVE  MINERALOGY  [SEC.  2 

H. 

Color  dark  gray,  black,  brownish  black,  reddish  brown.  Streak  brownish 
black,  black.  Luster  metallic,  submetallic.  Opaque.  May  be  slightly  mag- 
netic. (See  pp.  204,  222,  242.) 

In  veins  in  granite  with  cassiterite,  quartz,  mica,  fluorite,  apatite,  scheelite, 
pyrite,  galena,  sphalerite;  also  in  sands. 

5  G.  4.5-5.0    ILMENITE  (Menaccanite,  Titanic  Iron  Ore),  FeTiO3;  Fe  36.8%. 

6  Ti  31.6%;  sometimes  Mg. 

Struct. — Thin  plates,  granular,  compact,  disseminated;  pebbles,  sand; 
thick  tabular  hexagonal-rhombohedral  crystals.  Cleavage  none;  sometimes 
partings;  brittle;  fracture  conchoidal. 

Color  and  streak  iron-black,  brownish  black.  Luster  metallic,  submetallic. 
Opaque.  May  be  slightly  magnetic.  (See  pp.  206,  210.) 

Disseminated  and  masses  in  igneous  rocks,  gneiss,  schist;  with  hematite, 
magnetite,  titanite,  apatite,  rutile,  quartz.  Common  in  black  sands. 

5  G.  3.7-4.7    PSILOMELANE  (Black  Hematite),  Mn02,  MnO,  H2O,  BaO,  K2O. 

6  Struct. — Compact,  botryoidal,  reniform.  stalactitic;  no  crystals.     Cleav- 
age none;  brittle;  fracture  conchoidal,  uneven. 

Color  iron-black,  bluish  black,  steel-gray.  May  have  sooty  coating  of 
pyrolusite  or  be  in  layers  with  it.  Streak  black,  brownish  black.  Luster 
metallic,  dull.  Opaque.  (See  p.  208.) 

With  other  manganese  minerals,  limonite,  barite. 

5  G.  3.0^.3     WAD   (Bog  Manganese),  MnO2.  H2O;  often  Fe,  Si,  Al,  Ba,  Co. 

6  Black,  compact.     H 1-6.     (See  p.  17.) 

5|    G.  9.0-9.7    UBANINITE  (Pitchblende),  UOa,  U02,  Pb,  Th,  La,  Y,  He,  Ra,  etc. 

Struct. — Botryoidal,  granular,  lamellar,  compact;  isometric  crystals  rare. 
Cleavage  none;  brittle;  fracture  conchoidal. 

Color  greenish  or  brownish  black,  pitch-black.  Streak  brownish  black, 
grayish  black,  olive  green.  Luster  pitch-like,  submetallic,  dull.  Opaque. 
(See  p.  210.) 

With  ores  of  silver,  lead,  copper,  bismuth;  also  in  pegmatites. 

5}    G.  4.0-4.1    Ilvaite  (Lievrite),  CaFe3(OH)(SiO4)2. 

6  Struct. — Prismatic  orthorhombic  crystals,  striated  lengthwise;  columnar, 
compact.  Cleavage  indistinct,  two  directions  at  90°  (010)  (001);  brittle; 
fracture  uneven. 

Color  black,  greenish  to  brownish  black;  often  softer  yellowish  altered 
coating.  Streak  black  with  greenish  or  brownish  tinge.  Luster  submetallic, 
vitreous.  Opaque.  (See  pp.  206,  220.) 

In  limestone  and  dolomite;  with  pyroxene,  actinolite,  iron  minerals. 

5|    G.  4.9-5.2    MAGNETITE    (Magnetic    Iron   Ore),    FeFe,O4;     Fe   72.4%; 

65  sometimes  Mg,  Mn,  Ti. 

Struct. — Granular,  compact,  lamellar,  disseminated;  sand;  isometric  crys- 
tals, commonly  octahedrons  and  dodecahedrons  (Figs.  1,  7).  Cleavage 
none;  may  have  octahedral  parting  (111)  four  directions  at  70^°  and  109|°; 
brittle;  fracture  conchoidal,  uneven. 


SEC.  2, 3]  PHYSICAL  TABLES  23 

H. 

Color   iron-black.     Streak  black.     Luster   metallic.     Opaque.     Strongly 

attracted  by  magnet;  may  be  natural  magnet  (lohestone).    (See  pp.  204,  206.) 

Ore  bodies  and  disseminated  in  igneous  and  metamorphic  rocks;    black 

sands;  with  hornblende,  pyroxene,  feldspars,  chlorite,  pyrite,  apatite,  ilmenite, 


5i     G.  5.1-5.2    FRANKLINITE,    (Fe,Mn,Zn)(Fe,Mn)2O4;     Fe  39^7%;    Mn 
6|  10-20%;  Zn  5.5-18.5%. 

Struct. — Compact,    granular,    rounded   disseminated    grains;    isometric 

crystals  (octahedrons,  Fig.  1).     Cleavage  none;  indistinct  octahedral  parting 

(111)  four  directions  at  701°  and  lOO?0;  brittle;  fracture  conchoidal,  uneven. 

Color  iron-black.     Streak  black,  brownish  black,  reddish  brown.     Luster 

metallic,  dull.     Opaque.     May  be  slightly  magnetic.     (See  p.  208.) 

In  crystalline  limestone  (New  Jersey)  with  zincite,  willemite,  rhodonite, 
tephroite. 

6      G.  5.3-7.3    COLUMBITE,  (Fe,Mn)Cb2Oc;  with  Ta,  grading  into  Tantalite, 

(Fe,  Mn)Ta2O6;  latter  Ta2OB  up  to  86%. 

Struct. — Orthorhombic  crystals,  short,  square,  prismatic;  granular,  dis- 
seminated. Cleavage  indistinct,  one  direction  (100);  brittle;  fracture  con- 
choidal, uneven. 

Color  iron-black,  grayish  and  brownish  black;  may  be  iridescent.  Streak 
dark  red,  brownish  black,  black.  Luster  submetallic,  greasy,  dull.  Opaque. 
(See  pp.  204,  210,  242,  264.) 

In  pegmatite  with  beryl,  lepidolite,  tourmaline,  spodumene,  cassiterite. 

6      G.  4.7-4.8    Braunite,  3Mn2O3.MnSiO3;   Mn  64.4%. 

6^  Struct. — Granular;  drusy  crusts;  minute  tetragonal  crystals,  resembling 
octahedrons.  Cleavage  distinct,  four  directions  at  70°  and  110°  (111) ;  brittle; 
fracture  uneven. 

Color  brownish  black  to  steel-gray.  Streak  black,  brownish  black.  Luster 
submetallic,  greasy.  Opaque.  (See  p.  208.) 

With  manganese  minerals,  magnetite,  hematite,  barite. 


SECTION  3 

Streak  black  or  nearly  so ;  mineral  yellow,  red,  or  brown. 

2  G.  6.0-6.2    POLYBASITE,  (Ag,Cu)9SbS6;    Ag  62-72%;     Cu  3-10%;     some- 

3  times  As. 

Struct. — Tabular  six-sided  monoclinic  crystals  with  triangular  markings 
on  base;  granular,  compact,  disseminated.  Cleavage  imperfect,  one  direction 
(001);  brittle;  fracture  uneven. 

Color  iron-black;  in  thin  splinters  cherry-red.  Streak  black.  Luster 
metallic.  Nearly  opaque.  (See  p.  198.) 

In  veins  with  other  silver  minerals,  galena,  sphalerite;  replacements  in 
limestone. 


24  DETERMINATIVE  MINERALOGY  [SEC.  3 

H. 

2}     G.  9.0  CALAVERITE,  (Au,Ag)Te2;  Au  38-41%;  .Ag  2-4%. 

Struct. — Compact;  small  monoclinic  crystals  rare.  Cleavage  none; 
brittle;  fracture  uneven. 

Color  light  bronze-yellow.  Streak  yellowish  gray.  Luster  metallic. 
Opaque.  (See  p.  206.) 

In  veins  with  gold,  sylvanite,  petzite,  tetrahedrite,  pyrite,  fluorite. 

2%    G.  8.3-8.4    KRENNERITE,  AuAgTe4;  Au  24.5%;  Ag  13.4%. 

Struct. — Small  prismatic  orthorhombic  crystals  striated  lengthwise. 
Cleavage  distinct  crosswise  (001);  brittle;  fracture  uneven. 

Color  silver-white  to  brass-yellow.  Streak  steel-gray.  Luster  metallic. 
Opaque.  (See  p.  206.) 

In  veins  with  sylvanite,  calaverite,  molybdenite,  pyrite,  fluorite. 

3      G.  4.9-5.4     BORNITE    (Erubescite,    Purple    Copper,    Variegated    Copper, 

Peacock  Ore,  Horseflesh  Ore),  Cu6FeS4;    Cu  63.3%. 
Struct. — Compact,  granular;    isometric  crystals  (cubes)  rare;     Cleavage 
none:'  brittle;  fracture  uneven. 

Color  copper-red  to  bronze-brown;    tarnish  deep  blue,  purple,  and  varie- 
gated.    Streak  grayish  black.     Luster  metallic.     Opaque.     (See  p.  200.) 
In  veins  and  ore  deposits  with  other  copper  minerals,  pyrite,  siderite. 

3      G.  8.1-8.2     Altaite,  PbTe;   Pb  62.3%. 

Struct. — Compact;  rarely  isometric  crystals.  Cleavage  three  directions 
at  90°  (100);  sectile;  fracture  uneven. 

Color  tin-white,  yellowish;  tarnish  bronze-yellow.  Streak  gray.  Luster 
metallic.  Opaque.  (See  p.  206.) 

In  veins  with  other  tellurides,  native  tellurium,  pyrite,  galena,  tetrahedrite. 

3  G.  5.3-5.7     MILLERITE  (Capillary  Pyrites,  Nickel  Pyrites),  NiS;  Ni  64.7%. 
3s        Struct. — Needle-like    to    hair-like     crystals     (hexagonal-rhombohedral) ; 

fibrous  crusts,  compact.  Cleavage  rhombohedral,  difficult  to  observe; 
brittle;  slender  crystals  elastic;  fracture  splintery,  uneven. 

Color  brass-yellow,  bronze-yellow.  Streak  greenish  black.  Luster 
metallic.  Opaque.  (See  p.  202.) 

In  cavities  in  hematite  ore  and  limestone;  with  pyrrhotite,  chalcopyrite, 
chloanthite,  barite,  fluorite,  siderite. 

3J    G.  4.1-4.3    CHALCOPYRITE     (Copper    Pyrites,    Yellow    Copper    Ore), 

4  CuFeSz;  Cu  34.5%. 

Struct. — Compact,  granular,  disseminated;  sometimes  tetragonal  crystals 
resembling  tetrahedrons.  Cleavage  indistinct;  brittle;  fracture  uneven. 

Color  brass-yellow,  golden  yellow;  tarnish  often  iridescent  or  deep  blue, 
purple,  and  black.  Streak  greenish  black.  Luster  metallic.  Opaque. 
(See  p.  200.) 

In  schists,  veins,  and  contact  deposits  with  quartz,  calcite,  pyrite,  bornite, 
chalcocite,  galena,  sphalerite. 


SEC.  3]  PHYSICAL  TABLES  25 

H. 

3J    G.  4.6-5.1    PENTLANDITE  (Fe,Ni)S;    Ni  18-40%. 

4          Struct. — Granular,  compact;    isometric  crystals  rare.     Cleavage  distinct, 
four  directions  at  70£°  and  109£°  (111);  brittle;  fracture  uneven. 

Color  light  bronze-yellow.  Streak  black.  Luster  metallic.  Opaque. 
(Seep.  202.) 

In  nickel  ores  with  chalcopyrite  and  pyrrhotite. 

3|     G.  4.5-4.6    PYRRHOTITE  (Pyrrhotine,  Magnetic  Pyrites,  Mundic),  FeS; 
4|  S  36.4%;  may  have  up  to  3.5%  additional  S  in  solution. 

Struct. — Compact,  granular;  tabular  hexagonal  crystals  rare.  Cleavage 
indistinct,  one  direction  (0001);  brittle;  fracture  uneven. 

Color  yellowish  to  brownish  bronze;  tarnish  dark  brown.  Streak  dark 
grayish  black.  Luster  metallic.  Opaque.  Particles  generally  attracted  by 
magnet.  (See  p.  200.) 

In  veins,  schists,  contacts,  with  pyrite,  chalcopyrite,  pentlandite,  galena, 
apatite;  accessory  in  basic  igneous  rocks;  in  magmatic  segregations. 

4  G.  4.3-4.5     Stannite  (Tin  Pyrites'),  Cu2FeSnS4;   Sn  27.5%. 

May  be  brass-yellow  from  admixture  of  chalcopyrite.     (See  p.  15.) 

5  G.  7.2-7.5    WOLFRAMITE    (Wolfram),    (Fe,Mn)WO4;    grades  into  Fer- 
5%  berite,  FeWO4,  and  Huebnerite,  MnWO4;  WO3  about  76%. 

Struct. — Thick  tabular,  short  columnar,  and  bladed  monoclinic  crystals, 
resembling  orthorhombic ;  cleavable,  granular,  compact.  Cleavage  perfect, 
one  direction  (010) ;  brittle;  fracture  uneven. 

Color  dark  gray,  black,  brownish  black,  reddish  brown.  Streak  brownish 
black,  black.  Luster  metallic,  submetallic.  Opaque.  May  be  slightly 
magnetic.  (See  pp.  204,  222,  242.) 

In  veins  in  granite  with  cassiterite,  quartz,  mica,  fluorite,  apatite,  scheel- 
ite,  pyrite,  galena,  sphalerite;  also  in  sands. 

5      G.  7.3-7.7     NICCOLITE  (Copper  Nickel),  NiAs;  Ni  43.9%;  some  Fe,  Co,  Sb,  S. 
5J         Struct. — Compact,  disseminated;   small  hexagonal  crystals  rare.     Cleav- 
age none;   brittle;   fracture  uneven. 

Color  light  copper-red;  tarnish  gray  to  blackish.  May  have  coating  of 
green  (annabergite) .  Streak  brownish  black.  Luster  metallic.  Opaque. 
(See  p.  196.) 

With  cobalt,  nickel,  and  silver  minerals,  bismuth,  arsenic,  calcite. 

5}     G.  6.0-6.3     COBALTITE    (Cobalt  Glance),   CoAsS;     Co  35.5%;    As  45.2%; 

some  Fe. 

Struct. — Isometric  crystals  (cubes,  pyritohedrons,  Figs.  5, 18,  20);  granular, 
compact.  Cleavage  indistinct,  three  directions  at  90°  (100);  brittle;  fracture 
uneven. 

Color  silver-white  to  gray,  sometimes  reddish.  Streak  grayish  black. 
Luster  metallic.  Opaque.  (See  p.  196.) 

With  silver,  smaltite,  niccolite,  pyrrhotite,  chalcopyrite;  often  with  pink 
coating  of  erythrite  (cobalt  bloom.) 


26  DETERMINATIVE  MINERALOGY  [SEC.  3,  4 

H. 

6       G.  4.9-5.2     PYRITE  (Pyrites,  Iron  Pyrites,  White  Iron,  Fool's  Gold),  FeS2; 

6|  S  53.3%;   Fe  46.7%;  sometimes  Ni,  Co,  Cu,  Au. 

Struct. — Isometric  crystals,  cubes,  pyritohedrons,  octahedrons  (Figs.  1,  5, 
18,  20),  often  striated;  compact,  granular,  botryoidal,  stalactitic.  Cleavage 
none;  brittle;  fracture  uneven. 

Color  pale  to  full  brass-yellow;  tarnish  brown,  variegated,  sometimes 
iridescent.  Streak  greenish  black,  brownish  black.  Luster  metallic.  Opaque. 
(See  p.  200.) 

Lenticular  bodies  in  schists;  concretions,  disseminated  in  clay,  shale,  coal; 
in  veins  with  other  sulphides;  accessory  in  all  kinds  of  rocks. 

6  G.  4.8-4.9  MARCASITE  (White  Iron  Pyrites,  White  Iron),  FeS2;  Fe 
6|  46.6%;  S53.4%. 

Struct. — Tabular  orthorhombic  crystals  and  twin  groups,  often  cocks- 
comb or  spear-head  forms  (cockscomb  pyrites,  spearhead  pyrites)',  compact, 
stalactitic,  rounded  concretions.  Cleavage  indistinct,  two  directions  at  75° 
and  105°  (110);  brittle;  fracture  uneven. 

Color  pale  brass-yellow  to  almost  white;  tarnish  deeper  yellow  to  brown. 
Streak  dark  greenish  to  brownish  black.  Luster  metallic.  Opaque.  (See 
p.  200.) 

Alters  readily  on  exposure  to  capillary  melanterite  and  to  limonite;  much 
less  stable  than  pyrite.  With  lead  and  zinc  ores,  pyrite,  chalcopyrite,  cinna- 
bar; concretions  in  clay,  shale,  and  coal. 

6      G.  4.7-4.8    Braunite,  3Mn203-MnSi03;   Mn  64.4%. 

6|  Struct. — Granular,  drusy  crusts;  minute  tetragonal  crystals,  resembling 
octahedrons.  Cleavage  distinct,  four  directions  at  70°  and  110°  (111); 
brittle;  fracture  uneven. 

Color  brownish  black  to  steel-gray.  Streak  black,  brownish  black.  Luster 
submetallic,  greasy.  Opaque.  (See  p.  208.) 

With  manganese  minerals,  magnetite,  hematite,  barite. 


SECTION  4 
Streak  silver-white  to  steel-gray. 

G.  13.6         Mercury  (Native  Mercury,  Quicksilver),  Hg;   sometimes  Ag. 
Struct. — Small  liquid  globules;  isometric  crystals  (octahedrons)  at  —39°  C. 

Cleavage  cubic;  sp.  g.  of  crystals  14.4. 

Color  tin-white.    Luster  metallic.     Opaque.     (See  p.  202.) 

With  cinnabar  and  other  mercury  minerals  and  quartz,  in  shales,  schists, 

some  hot  springs. 

G.  7.9-8.3    SYLVAWITE,  AuAgTe4;  Au  24.5%  Agl3.4%. 

Struct. — Branching  aggregates,  some  like  ancient  script  (graphic  tellurium) ; 
bladed,  columnar,  granular;  monoclinic  crystals  rare;.  Cleavage  distinct, 
one  direction  (010);  brittle;  fracture  uneven. 


SEC.  4]  PHYSICAL  TABLES  27 

H. 

Color  silver- white  to  steel-gray,  sometimes  brassy  tinge.  Streak  whitish 
steel-gray.  Luster  metallic.  Opaque.  (See  p.  206.) 

In  veins  with  gold,  calaverite,  sphalerite,  pyrite,  tetrahedrite. 

2      G.  9.7-9.8    BISMUTH  (Native  Bismuth),  Bi;  of  ten  also  As,  S,  Te. 
2|        Struct. — Laminated,  granular,  branching,  disseminated;    rarely  distinct 
hexagonal-rhombohedral  crystals.     Cleavage  distinct,  one  direction  crosswise 
(0001);  sectile;  somewhat  malleable. 

Color  silver-white,  reddish;  tarnish  often  brassy.  Streak  silver-white, 
shiny.  Luster  metallic.  Opaque.  (See  p.  202.) 

With  ores  of  silver,  cobalt,  nickel,  lead,  zinc,  tin,  tungsten. 

2  G.  6.1-6.3     Tellurium  (Native  Tellurium),  Te;  sometimes  Se,  Au,  Fe. 

2£  Struct. — Fine  granular,  columnar,  compact;  minute  hexagonal-rhombo- 
hedral prisms.  Cleavage  distinct,  three  directions  lengthwise  at  60°  and  120° 
(1010) ;  somewhat  brittle. 

Color  and  streak  tin-white.    Luster  metallic.     Opaque.     (See  p.  206.) 

In  veins  with  quartz,  pyrite,  gold. 

2|     G.  9.0  CALAVERITE,  (Au,Ag)Te2;  Au  38-41%;  Ag  2-4%. 

Struct. — Compact;  small  monoclinic  crystals  rare.  Cleavage  none; 
brittle;  fracture  uneven. 

Color  light  bronze-yellow.  Streak  yellowish  gray.  Luster  metallic. 
Opaque.  (See  p.  206.) 

In  veins  with  gold,  sylvanite,  petzite,  tetrahedrite,  pyrite,  fluorite. 

2J    G.  8.3-8.4    KRENNERITE,  AuAgTe4;  Au  24.5%;  Ag  13.4%. 

Struct. — Small  prismatic  orthorhombic  crystals  striated  lengthwise. 
Cleavage  distinct,  one  direction  crosswise  (001);  brittle;  fracture  uneven. 

Color  silver-white  to  brass-yellow.  Streak  steel-gray.  Luster  metallic. 
Opaque.  (See  p.  206.) 

In  veins  with  sylvanite,  calaverite,  molybdenite,  pyrite,  fluorite. 

2£     G.  10-12      SILVER  (Native  Silver),  Ag;    some  Au,  Cu. 

3  Struct. — Grains,  scales,  plates,  wire;    isometric  crystals  commonly  dis- 
torted.    Cleavage  none;   malleable  and  ductile;  fracture  hackly. 

Color  silver-white;  tarnish  yellow,  brown,  black.  Streak  silver-white  to 
light  lead-gray,  shiny.  Luster  metallic.  Opaque.  (See  p.  202.) 

In  veins  with  silver,  copper,  and  lead  minerals,  fluorite,  calcite,  barite, 
stibnite. 

2J    G.  8.3-8.5    HESSITE,  A&Te;  Ag  63.3%;  often  some  Au. 
3          Struct. — Fine  grained  to  compact;    isometric   crystals  rare.     Cleavage 
none;  somewhat  sectile;  fracture  uneven. 

Color  steel-gray  to  lead-gray.  Streak  gray.  Luster  metallic.  Opaque. 
(See  p.  206.) 

In  veins  with  other  tellurides,  pyrite,  chalcopyrite,  fluorite. 


28  DETERMINATIVE  MINERALOGY  [Sac.  4 

H. 

1\    G.  8.7-9.0    PETZITE,  AgaAuTe^;  Ag  42%;  Au  25.5%. 
3         Struct. — Granular,  compact.     Cleavage  none;    slightly  sectile  to  brittle; 
fracture  uneven. 

Color  steel-gray  to  iron-black.  Streak  steel-gray.  Luster  metallic. 
Opaque.  (See  p.  206.) 

In  veins  with  hessite,  calaverite,  altaite,  pyrite,  siderite,  quartz,  gold. 

3      G.  8.1-8.2    Altaite,  PbTe;  Pb  62.3%;  some  Ag  and  Au. 

Struct. — Compact;  rarely  isometric  crystals.  Cleavage  three  directions 
at  90°  (100);  sectile;  fracture  uneven. 

Color  tin-white,  yellowish;  tarnish  bronze-yellow.  Streak  gray.  Luster 
metallic.  Opaque.  (See  p.  206.) 

In  veins  with  other  tellurides,  native  tellurium,  pyrite,  galena,  tetrahedrite. 

3      G.  13.7-14.1     Amalgam  (Silver  Amalgam),  (Ag,Hg);   Ag  27.5-95.8%. 
3£        Struct. — Plates,    coatings,    imbedded   grains;    rarely   isometric   crystals; 
Cleavage  none;  brittle  to  malleable;  fracture  conchoidal,  uneven. 

Color  and  streak  silver-white.  Luster  metallic,  brilliant.  Opaque.  (See 
p.  202.) 

In  veins  with  mercury  and  silver  minerals. 

3      G.  6.6-6.7    Antimony  (Native  Antimony),  Sb;   sometimes  Ag,  Fe,  As. 
3|        Struct. — Granular,    cleavable,    radiated,    botryoidal;     rarely   hexagonal- 
rhombohedral  crystals.      Cleavage  distinct,  one  direction   (0001);     brittle; 
fracture  uneven. 

Color  and  streak  tin-white  to  light  steel-gray.  Luster  metallic.  Opaque. 
(See  p.  198.) 

In  veins  with  silver,  arsenic,  and  antimony  minerals. 

3  G.  5.6-5.7    ARSENIC  (Native  A  rsenic),  As;  often  some  Sb. 

4  Struct. — Mammillary,  concentric   crusts,   scaly,    fine   grained,    compact; 
hexagonal-rhombohedral    crystals    rare.     Cleavage    distinct,    one    direction 
(0001);  brittle;   fracture  uneven. 

Color  and  streak  tin-white,  tarnishing  soon  to  dark  gray.  Luster  metallic. 
Opaque.  (See  p.  196.) 

In  veins  with  antimony  minerals,  ruby  silver  ores,  realgar,  orpiment, 
sphalerite. 

3£    G.  9.4-9.9     Dyscrasite  (Antimonial  Silver),  Ag3Sb  to  AgeSb;  Ag  73-84%. 

Struct. — Compact,  granular,  incrusting;  rarely  columnar  and  tabular 
orthorhombic  (pseudohexagonal)  crystals.  Cleavage  distinct,  three  direc- 
tions at  56°,  68°,  and  124°  (Oil)  (001);  sectile;  fracture  uneven. 

Color  silver-white  to  tin-white;  tarnish  yellow  to  black.  Streak  silver- 
white,  tin-white,  shiny.  Luster  metallic.  Opaque.  (See  p.  198.) 

In  veins  with  galena,  arsenic,  pyrargyrite,  native  silver,  smaltite. 


SEC.  4, 5]  PHYSICAL  TABLES  29 

H. 

4      G.  14-19       PLATINUM  (Native  Platinum),  Pt;  Fe  up  to  15%,  also  Pd,  Rh, 
4§  Ir,  Os 

Struct. — Grains,  scales,  lumps;  rarely  distorted  isometric  crystals;     Cleav- 
age   none;   malleable,  ductile;   fracture  hackly. 

Color    tin-white,  steel-gray;    does  not  tarnish.      Streak  light  steel-gray, 
shiny.     Luster  metallic.     Opaque.     May  be  magnetic.      (See  p.  210.) 
In  placers  with  gold,  chromite,  iridium. 

6  G.  22.6-22.8    Iridium  (Native  Iridium,  Platiniridium) ,  Ir;  somePt,  Pd,  Rh. 

7  Struct. — Angular  grains;   isometric  crystals  rare.     Cleavage  none;   some- 
what malleable;   fracture  hackly. 

Color  silver-white  with  yellowish  tinge,  gray  on  fracture.     Streak  light 
gray.    Luster  metallic.     Opaque.     (Seep.  210.) 
In  placers  with  platinum,  gold,  chromite. 

6  G.  18.9-21.2     Iridosmium  (Iridosmine,  Osmiridium),  Ir,  Os;  also  Rh,  Pt,  Ru. 

7  Struct. — Scales,   flattened  grains;    rarely  hexagonal   crystals.     Cleavage 
distinct,  one  direction  (0001) ;   slightly  malleable;   fracture  uneven. 

Color  tin-white  to  light  steel-gray.     Streak  grayish.    Luster  metallic. 
Opaque.     (See  p.  210.) 

In  placers  with  platinum,  gold,  chromite 


SECTION  6 

Streak  chalk-white,   colorless,  or  pale  colored;    mineral  white, 
colorless,  or  pale  colored;   distinct  cleavage  in  one  direction  only. 

0  G.  1.4-1.5    Sassolite  (Native  Boric  Acid),  H3BO3;   B2O3  56.4%. 

1  Struct. — Small  pearly  scales;  rarely  thin  tabular  triclinic  crystals.     Cleav- 
age perfect,  one  direction  (001);  .greasy  feel;   brittle. 

Color  white,  grayish,  yellowish.     Streak  white.     Luster  pearly.     Trans- 
lucent.    Acid  taste.      (See  p.  228.) 

In  hot  lagoons,  fumaroles,  volcanic  craters,  lakes,  springs. 

1  G.  2.8-2.9    PTBOPHYLLITE  (Pencil  Stone),  H2Al2(Si03)2. 

2  Struct. — Foliated,  granular,  fibrous,  radial,    compact;    indistinct    ortho- 
rhombic    crystals   rare.      Cleavage   perfect,    one    direction    (001);    fracture 
uneven,  splintery;  thin  flakes  flexible,  not  elastic;  feel  greasy. 

Color  white,  apple-green,  gray,  yellow.     Streak  white.    Luster  Dearly  to 
dull.     Translucent  to  opaque.     (See  p.  256.) 

In  schistose  rocks  with  cyanite,  topaz,  graphite,  lazulite. 

1      G.  2.5-2.8    TALC  (Steatite,  Soapstone,  Potstone),  H2Mg3(SiO3)4. 

2 1        Struct. — Foliated,    granular;    fibrous    (agolite);     compact    (soft,    French 

chalk;     waxy,    rensselaerite) ;     indistinct-  tabular    monoclinic    crystals   rare. 

Cleavage  perfect,  one  direction  (001);   fracture  uneven;   sectile;   thin  flakes 

flexible,  not  elastic;  greasy  feel.     H.  sometimes  3-4. 


30  DETERMINATIVE  MINERALOGY  [SEC.  5 

H. 

Color  apple-green,  gray,  white.  Streak  white.  Luster  pearly,  greasy. 
Transparent  to  opaque.  (See  pp.  236,  246,  256.) 

In  crystalline  schists;  with  serpentine,  dolomite,  magnesite,  chlorite, 
actinolite. 

li     G.  2.6-2.7    VIVIANITE  (Blue  Iron  Earth),  Fe3(PO4)2-8H2O;  P2O6  28.3%. 
2          Struct. — Radial  fibrous,  earthy;    prismatic  and  tabular  monoclinic  crys- 
tals.    Cleavage  distinct,  one   direction  (010);    sectile;    thin  flakes  flexible; 
fracture  splintery,  earthy. 

Color  blue,  green,  greenish  black;  colorless  when  fresh.  Streak  white, 
blue,  greenish  blue.  Luster  pearly  on  cleavage;  vitreous,  dull.  Trans- 
parent to  opaque.  (See  p.  218.) 

In  clay,  marl,  peat;  in  cavities  of  fossils;  with  limonite;  in  veins  with 
pyrrhotite,  pyrite,  gold. 

1|     G.  2.3-2.4    GYPSUM  (Selenite,  Alabaster,  Satin  Spar),  CaSO4-2H2O. 
2          Struct. — Granular,  foliated,   fibrous;    earthy   (gypsite);    diamond-shaped 
monoclinic  crystals  with  beveled  edges  (Figs.  38,  39).     Cleavage  perfect,  one 
direction  (010);  two  others  less  conspicuous  (111)  (100)  at  90°,  66°,  114°; 
brittle;  thin  flakes  flexible;  fracture  conchoidal,  splintery. 

Color  white,  colorless,  gray,  yellow,  red.  Streak  white.  Luster  vitreous; 
pearly  on  (010);  silky.  Transparent  to  opaque.  (See  pp.  224,  226.) 

Beds  and  masses  with  limestone,  shale,  clay,  rock  salt;  near  volcanic  vents; 
with  anhydrite,  celestite,  sulphur,  calcite,  aragonite. 

2      G.  2.3-2.4     BRUCITE,  Mg(OH)2;  sometimes  Fe  and  Mn. 
2  5        Struct. — Foliated,  scaly;  fibrous   (nemalite);    rarely  broad  tabular  hexa- 
gonal-rhombohedral  crystals.     Cleavage  perfect,  one  direction  (0001);  sectile; 
thin  flakes  and  fibers  flexible. 

Color  white,  grayish,  bluish,  greenish.  Streak  white.  Luster  pearly, 
on  cleavage;  vitreous,  waxy.  Transparent  to  translucent.  (See  pp.  248, 
252.) 

With  serpentine,  dolomite,  magnesite,  chromite. 

2      G.  1.7  BORAX  (Tinkal),  Na2B4O7-  10H2O;   B2O3  36.6%. 

2 1        Struct. — Compact,  earthy,  incrusting;  short  columnar  monoclinic  crystals. 
Cleavage  distinct,  one  direction  (100);  brittle;  fracture  conchoidal. 

Color  white,  colorless,  grayish,  bluish,  greenish.  Streak  white.  Luster 
vitreous,  greasy.  Translucent  to  opaque.  Sweetish  alkaline  taste.  (See 
pp.  226,  228.) 

In  mud  of  alkaline  lakes  and  marshes  with  halite,  gypsum,  colemanite. 

2  G.  2.7-3.0     MUSCOVITE  (Common  or  White  Mica,  Potash  Mica.  Isinglass), 

3  H2KAl3(SiO4)3;  often  a  little  Na,  Ca,  Mg,  Fe,  and  F. 
Struct. — Foliated,  flaky;  fine  scaly  to  fibrous  (sericite,  damourite);  dense 

(pinite);  rarely  distinct  monoclinic  (pseudohexagonal)  crystals.  Cleavage 
perfect,  one  direction  (001);  thin  flakes  tough,  very  elastic. 

Color  white,  gray,  yellowish,  greenish,  brownish.  Streak  white.  Luster 
vitreous,  pearly.  Transparent  to  translucent.  (See  p.  236.) 

In  pegmatite,  granite,  gneiss,  schists,  contacts;  with  feldspars,  quartz, 
tourmaline,  beryl,  garnet. 


SEC.  5]  PHYSICAL  TABLES  31 

H. 

2  G.  2.8-2.9    PHLOGOPITE  (Amber  Mica,  Bronze  Mica,  Magnesia  Mica), 

3  H2KMg3Al(SiO4)3;   some  F  and  Fe. 

Struct. — Plates,  scales;  prismatic  or  tabular  monoclinic  crystals  with 
hexagonal  or  orthorhombic  outline,  commonly  rough.  Cleavage  conspicuous, 
one  direction  (001);  tough;  laminae  very  elastic. 

Color  yellowish  brown,  brownish  red,  gray  to  green;  rarely  colorless. 
Streak  white.  Luster  pearly,  submetallic.  Translucent  to  transparent. 
(See  pp.  204,  236.) 

Contacts  in  crystalline  limestone;  in  serpentine;  with  pyroxene,  amphi- 
bole,  serpentine,  graphite,  apatite,  corundum. 

2  G.  2.8-2.9    LEPIDOLITE    (Lithia   Mica},    (Li,K)2Al2(OH,F)2(SiO3)j; 

3  Li2O  3.8-5.8%. 

Struct. — Foliated,  scaly,  compact;  rarely  monoclinic  crystals,  small  tabular 
or  prismatic.  Cleavage  perfect,  one  direction  (001) ;  laminae  tough,  elastic. 

Color  pink,  lilac,  yellowish,  grayish  white,  white.  Streak  white.  Luster 
pearly.  Translucent.  (See  p.  236.) 

In  pegmatite  with  pink  and  green  tourmaline,  cassiterite,  topaz,  amblygo- 
nite,  spodumene. 

2  G.  2.8-2.9     Paragonite  (Soda  Mica),  H2NaAl3(SiO4)3. 

3  Fine  scaly  masses,  compact;  strong  pearly  luster.     Otherwise  like  musco- 
vite,  above.     In  schists  with  cyanite,  staurolite,  tourmaline,  garnet,  actino- 
lite.     (See  p.  236.) 

2  G.  2.7  THENARDITE,  NatSO4;  Na*O  56.3%. 

3  Struct. — Orthorhombic  crystals,  often  cross  twins;    granular.     Cleavage 
one  direction  (001) ;  brittle;  fracture  uneven. 

Color  white  to  brownish.     Streak  white.     Luster  vitreous.     Transparent 
to  translucent.     Soluble  in  water.     (See  p.  224.) 
About  salt  lakes  and  dry  lake  beds. 

2J     G.  2.7-2.8    Glauberite,  Na2Ca(SO4)2. 

Struct. — Thick  tabular  monoclinic  crystals;  reniform,  lamellar.     Cleav- 
age distinct,  one  direction  (001);  brittle;  fracture  conchoidal. 

Color  white,  colorless,  yellowish,  grayish;  white  powdery  coating  forms  on 
exposure.  Streak  white.  Luster  vitreous,  greasy.  Transparent  to  translu- 
cent. Taste  slightly  salty.  (See  p.  226.) 

With  halite,  thenardite,  mirabilite,  hanksite,  ulexite. 

21     G.  6.2-6.5     Leadhillite,  Pb4(OH)2(C03)2SO4. 

Struct. — Tabular  monoclinic  (pseudohexagonal)  crystals  and  twins;  com- 
pact, lamellar.  Cleavage  perfect,  one  direction  (001) ;  rather  sectile;  fracture 
conchoidal,  rarely  observable. 

Color  white,  colorless,  yellow,  green,  gray.  Streak  white.  Luster  pearly, 
adamantine.  Transparent  to  translucent.  (See  p.  214.) 

Twins  and  trillings  like  aragonite,  but  very  heavy.     Occurs  sparingly 
with  lead  ores. 


32  DETERMINATIVE  MINERALOGY  [SEC.  5 


1\    G.  2.1-2.2    TRONA(tfrao),  HNa3(CO3)2-2H2O. 

3          Struct.  —  Incrusting;    tabular  or  acicular  monoclinic  crystals.     Cleavage 
one  direction  (100);   brittle;   fracture  uneven. 

Color  white,  colorless,  yellowish,  grayish.  Streak  white.  Luster  vitre- 
ous, pearly.  Translucent.  Alkaline  taste.  (See  p.  224.) 

Efflorescence;  crusts  about  soda  lakes;  in  beds  with  halite,  glauberite, 
mirabilite,  hanksite. 

8J    G.  2.7-2.8    Polyhalite,  K2MgCas(SO4)4.2H2O;  K2O  15.6%. 
3          Struct.  —  Fibrous,  lamellar,  compact;   monoclinic  (?).     Cleavage  distinct, 
one  direction;  brittle;  fracture  splintery. 

Color  flesh  to  brick  -red;    yellowish  red  to  white.     Streak  white,  reddish 
to  yellowish  white.     Luster  greasy,  pearly.     Translucent  to  opaque.     Taste 
weakly  bitter  and  astringent.     (See  p.  226.) 
In  beds  of  salt,  gypsum,  and  clay. 

3  G.  2.5-2.8    TALC  (Steatite,  Soapstone,  Potslone),  H2Mg3(SiO3)4. 

4  Struct.  —  Foliated,  granular;  fibrous  (agolite)',  compact  (soft,  French  chalk; 
waxy,  rensselaerite)  ;    indistinct  tabular  monoclinic  crystals  rare.     Cleavage 
perfect,  one  direction  (001);  fracture  uneven;  sectile;  thin  flakes  flexible,  not 
elastic;  greasy  feel.     H.  commonly  1-2|. 

Color  apple-green,  gray,  white.  Streak  white.  Luster  pearly,  greasy. 
Transparent  to  opaque.  (See  pp.  236,  246,  256.) 

In  crystalline  schists;  with  serpentine,  dolomite,  magnesite,  chlorite, 
actinolite. 

3|    G.  2.1-2.2    STILBITE  (Desmine,  a  zeolite),  H4(Ca,Na2)Al2(SiO3)6.4H2O. 
4          Struct.  —  Sheaf  -like,  radial,  globular;    tabular  monoclinic  crystals,  com- 
monly in  twinned  groups,  orthorhombic  in  appearance.     Cleavage  distinct, 
one  direction  (010);    brittle;    fracture  uneven. 

Color  white,  grayish,  yellowish,  red  to  brown.  Streak  white.  Luster 
vitreous;  pearly  on  cleavage.  Translucent.  (See  p.  234.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous  veins; 
with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite,  quartz, 
epidote,  pyrite,  chalcopyrite,  chlorite. 

3|    G.  2.2  HETJLANDITE  (a  zeolite),  H^Ca^a-O  Al2(SiO3)6  •  3H2O. 

4  Struct.  —  Tabular  monoclinic  crystals,  often  look  orthorhombic;    dia- 

mond-shaped, striated;    foliated,  globular,  granular.     Cleavage  prominent, 
one  direction  (010)  ;  brittle;  fracture  uneven. 

Color  white,  grayish,  red,  brown.     Streak  white.     Luster  vitreous;  pearly 
on  cleavage.     Transparent  to  translucent.     (See  p.  234.) 
Occurrence  and  associations  as  for  stilbite,  above. 

3£     G.  3.0-3.1     MARGARITE  (Brittle  Mica),  H2CaAL,S2Oi2;  some  Fe,  Na,  K. 
4^        Struct.  —  Micaceous,  scaly,  granular;  six-sided  scales,  plates  (monoclinic). 
Cleavage  perfect,  one  direction  (001);  flakes  rather  brittle,  not  elastic. 

Color  pink,  grayish,  white,  yellowish.  Streak  white.  Luster  pearly 
on  cleavage;  vitreous.  Translucent.  (See  pp.  236,  256.) 

Coating  or  associated  with  corundum;  also  chlorite,  spinel,  emery,  diaspore. 


SEC.  5]  PHYSICAL  TABLES  33 


G.  2.3-2.4    APOPHYLLITE,  (H,K)2Ca(Si03)2-H20;  a  little  F. 

Struct.  —  Square,  tabular,  or  cube-like  tetragonal  crystals;  lamellar,  granu- 
lar, compact.  Cleavage  perfect,  one  direction  (001);  brittle;  fracture  un- 
even. 

Color  white,  greenish,  yellowish,  reddish.  Streak  white.  Luster  vitre- 
ous; pearly  on  cleavage.  Transparent  to  nearly  opaque.  (See  p.  234.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous  veins; 
with  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite,  quartz, 
epidote,  pyrite,  chalcopyrite,  chlorite. 


6      G.  3.2-3.4    ZOISITE,  Ca^AMOHXSiOOa;  often  some  Fe. 
65        Struct.  —  Columnar,   bladed,   fibrous,    compact;    prismatic  orthorhombic 
crystals  striated  lengthwise,  without  terminations.     Cleavage  conspicuous, 
one  direction  lengthwise  (010)  ;  brittle;  fracture  uneven. 

Color  gray,  yellowish  brown,  greenish;   also  red  (thulite).     Streak  white. 
Luster  vitreous;  pearly  on  cleavage.     Transparent  to  opaque.     (See  p.  246.) 
In  crystalline  schists  with  hornblende,  vesuvianite,  cyanite,  epidote,  garnet, 
feldspars,  quartz. 

6  G.  3.2-3.3    SILLIMANITE  (Fibrolite),  Al2SiO5,  or  Al(AlO)SiO4. 

7  Struct.  —  Fibrous,    columnar,    radiating;     slender    orthorhombic    crystals 
without  terminations.      Cleavage,   one  direction  lengthwise  (010);      brittle; 
fracture  splintery,  uneven. 

Color  grayish  white,  hair-brown,  greenish.  Streak  white.  Luster  vitre- 
ous, silky.  Transparent  to  translucent.  (See  p.  260.) 

In  gneiss;  in  contacts  of  aluminous  rocks;  with  andalusite,  cordierite, 
garnets,  corundum. 

6  G.  3.3-3.5    DIASPORE,  A1O.  OH;  Al  45%;  sometimes  Fe. 

7  Struct.  —  Scaly,  bladed,  fibrous;  columnar  and  tabular  orthorhombic  crys- 
tals rare.     Cleavage  distinct,  one  direction  (010)  ;  brittle;  fracture  conchoidal. 

Color  white,  grayish,  greenish,  hair-brown,  yellow,  colorless.  Streak 
white.  Luster  vitreous;  pearly  on  cleavage.  Transparent  to  opaque.  (See 
p.  260.) 

With  corundum,  emery,  dolomite,  margarite,  chlorite,  magnetite. 

6  G.  3.3-3.4    AXINITE,  HCa3Al2B(SiO4)4;   sometimes  Mn,  Fe,  Mg. 

7  Struct.  —  Tabular  wedge-shaped  triclinic  crystals  (Fig.  45)  ;  lamellar,  granu- 
lar.    Cleavage  distinct,  one  direction  (010);  brittle;  fracture  conchoidal. 

Color  clove-brown,  yellow,  greenish,  grayish  blue,  gray.     Streak  white. 
Luster  vitreous.     Transparent  to  translucent.     (See  p.  242.) 
In  veins  with  quartz,  feldspars,  hornblende,  chlorite. 

8  G.  3.4-3.6    TOPAZ,  Al2(F,OH)2SiO4. 

Struct.  —  Prismatic  orthorhombic  crystals,  many  striated  lengthwise; 
granular,  pebbles,  compact.  Cleavage  perfect,  one  direction  crosswise  (001); 
brittle;  fracture  conchoidal,  uneven. 


34  DETERMINATIVE  MINERALOGY  [SECS.  5,  6 

H. 

Color  white,  colorless,  yellow,  pink,  bluish,  greenish.  Streak  white. 
Luster  vitreous.  Transparent  to  opaque.  (See  p.  260.) 

Veins  in  pegmatite,  rhyolite,  granite;  contacts;  placers;  with  tourmaline, 
cassiterite,  apatite,  fluorite,  beryl,  garnet. 

SECTION  6 

Streak  chalk-white,  colorless,  or  pale  colored;    mineral  white, 
colorless,  or  pale  colored;   distinct  cleavage  two  directions. 

3J    G.  3.7  STRONTIANITE  (Strontian  Spar),  SrCO3;  SrO  70.1%;  some- 

4  times  Ca. 

Struct. — Chisel-  or  spear-shaped  orthorhombic  crystals,  pseudohexagonal 
prisms;  columnar,  acicular,  fibrous,  divergent;  granular,  compact.  Cleavage 
distinct,  two  directions  at  63°  and  117°  (110);  brittle;  fracture  uneven. 

Color  white,  colorless,  grayish,  greenish,  yellowish.  Streak  white.  Luster 
vitreous,  greasy.  Transparent  to  translucent.  (Seep.  246.) 

In  ore  deposits  with  galena,  barite,  calcite,  celestite,  fluorite,  pyrite;  veins 
in  limestone,  chalk,  marl. 

4      G.  2.3-2.5    COLEMANITE  (Priceile,  Pandermite),  HCa(BO2)3  •  2H2O. 
4^        Struct. — Short  prismatic  monoclinic  crystals;    cleavable,  granular,  com- 
pact, incrusting.     Cleavage  distinct,  two  directions  at  90°  (010)  (001) ;   frac- 
ture uneven,  conchoidal. 

Color  white,  colorless,  grayish,  yellowish.  Streak  white.  Luster  vitreous, 
dull.  Transparent  to  opaque.  (See  p.  228.) 

Pandermite  is  compact,  porcelain-like;  priceite  is  loosely  compacted, 
chalky.  Beds  in  sediments  with  gypsum,  celestite,  quartz. 

4      G.  2.2  Phillipsite  (a  zeolite),  (Ca,K2)Al2(SiO3)4-5H2O;  often  Na. 

4|  Struct. — Monoclinic  penetration  twins,  often  like  orthorhombic  or  tetra- 
gonal; radial  tufts  or  spheres.  Cleavage,  two  directions  at  90°  (010)  (001); 
brittle;  fracture  uneven. 

Color  white,  reddish.  Streak  white.  Luster  vitreous.  Translucent  to 
opaque.  (See  p.  232.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous  veins; 
with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite,  quartz, 
epidote,  pyrite,  chalcopyrite,  chlorite. 

4$    G.  2.4-2.5    HARMOTOME  (a  zeolite),  H2BaAl2(SiO3)5  •  4H2O;  some  Na  and  K. 

Struct. — Penetration  twins,  etc.  (monoclinic),  like  phillipsite,  above,  with 
cleavage,  fracture,  etc.,  the  same. 

Color  white,  grayish,  yellow,  red,  brown.  Streak  white.  Luster  vitreous. 
Translucent.  (See  pp.  232,  244.) 

Occurrence  and  associations  as  for  phillipsite,  above. 


SEC.  6]  PHYSICAL  TABLES  35 

H. 

4  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  Al2SiO6,  or  (AlO)2SiO3. 

5  Struct. — Long  tabular  or  bladed  triclinic  crystals  without  terminations, 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  length- 
wise at  74°  and  106°  (100)  (010);  transverse  parting  (001)  common;  brittle; 
fracture  splintery. 

Color  blue,  white,  gray,  green,  nearly  black;  often  streaked.  Streak 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  pp.  256,  260.) 

Hardness  lengthwise  4-5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum 

4  G.  4.4-4.6    XENOTIME,  YPO4;  also  Er,  Ce,  Th,  etc. 

5  Struct. — Tetragonal  crystals  (prism,  pyramid);    compact,  disseminated, 
rolled  grains.     Cleavage  distinct,  two  directions  at  90°  (110);   brittle;   frac- 
ture uneven,  splintery. 

Color  yellow,  brown,  red,  pale  gray.  Streak  pale  brown,  yellowish, 
reddish.  Luster  greasy,  vitreous.  Translucent  to  opaque.  (See  p.  256.) 

Like  zircon  but  softer.  In  pegmatite  and  granitic  rocks  with  zircon, 
rutile;  in  sands. 

4|  G.  3.4-3.5  CALAMINE  (Electric  Calamine,  Hemimarphite),  (ZnOH)2SiO3; 
5  Zn  54.2%. 

Struct. — Tabular  orthorhombic-hemimorphic  crystals,  commonly  diver- 
gent cockscomb  groups;  mammillary,  stalactitic,  granular.  Cleavage,  two 
directions  lengthwise  at  76°  and  104°  (110);  brittle;  fracture  uneven, 
conchoidal. 

Color  white,  colorless,  yellowish,  brownish,  greenish,  bluish.  Streak 
white.  Luster  vitreous,  adamantine,  dull.  Transparent  to  translucent. 
(See  p.  252.) 

In  oxidized  zinc  ores,  usually  in  limestone  or  clay,  with  smithsonite,  ceru- 
site,  anglesite,  galena,  sphalerite,  calcite,  limonite. 

4f    G.  2.8-2.9    WOLLASTONITE  (Tabular  Spar,  a  pyroxene),  CaSiO3. 
5          Struct. — Granular,  fibrous,  compact,  cleavable;   tabular  monoclinic  crys- 
tals.    Cleavage  distinct,  two  directions  at  84|°  and  95£°  (100)  (001);  brittle; 
fracture  uneven. 

Color  white,  grayish,  yellowish,  reddish,  brownish.     Streak  white.     Luster 
vitreous,  silky;  pearly  on  cleavage.     Translucent  to  opaque.     (See  p.  234.) 
In   limestone   contacts   with  pyroxene,   tremolite,    garnet,   vesuvianite, 
epidote,  graphite. 

5      G.  2.2-2.3    NATROLITE  (Needle  Zeolite},  Na2Al(AlO)(SiO3)3 •  2H20. 
5 1        Struct. — Slender     orthorhombic     (pseudotetragonal)     crystals;      fibrous, 
radial,  granular,  compact.     Cleavage,  two  directions  lengthwise  at  89°  and 
91°  (110);  brittle;  fracture  uneven. 

Color  white,  colorless,  grayish,  yellowish,  reddish.  Streak  white.  Luster 
vitreous,  silky.  Transparent  to  translucent.  (See  p.  230.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite, 
quartz,  epidote,  pyrite,  chalcopyrite,  chlorite. 


36  DETERMINATIVE  MINERALOGY  [SEC.  6 

H. 

5      G.  2.2-2 .4    Scolecite  (a  zeolite),  CaAl(A10)(SiO3)3-3H2O. 
5J        Struct. — Slender  prismatic  monoclinic  twin  crystals;    fibrous,  radiated, 
compact.     Cleavage  distinct,  two  directions  lengthwise  at  885°  and  91|°  (110) ; 
brittle;  fracture  splintery,  uneven. 

Color  white,  colorless.  Streak  white.  Luster  vitreous,  silky.  Trans- 
parent to  opaque.  (See  p.  230.) 

Occurrence  and  associations  as  for  natrolite,  on  preceding  page. 

5  G.  2.9-3.1    TREMOLITE  (Grammatite,  an  amphibole),  CaMg3(SiO3)4. 

6  Struct. — Bladed,  columnar,  fibrous,  compact;   bladed  monoclinic  crystals 
without  terminations;   prism  angle  and   cleavage  (distinct,  two  directions 
lengthwise)  at  56°  and  124°  (110);    brittle;    fracture  uneven;    small  fibers 
flexible  (asbestos).    Nephrite  or  jade,  in  part  tremolite,  is  dense,  compact,  tough. 

Color  white  to  dark  gray,  yellowish,  colorless.  Streak  white.  Luster 
vitreous,  silky,  pearly.  Transparent  to  opaque.  (See  p.  238.) 

In  limestone,  dolomite,  schist;  common  at  contacts;  with  pyroxene, 
garnet,  vesuvianite,  epidote,  wollastonite. 

5  G.  3.2-3.6    DIOPSIDE  (Malacolite,  a  pyroxene),  CaMg(SiO3)2;  some  Fe. 

6  Struct. — Prismatic    monoclinic    (pseudotetragonal)    crystals,    stout,    ter- 
minated (Figs.  40,  41);  lamellar,  granular  compact.     Cleavage  two  directions 
lengthwise  at  87°  and  93°  (110)  sometimes  distinct;  often  conspicuous  trans- 
verse parting  (001);   brittle;   fracture  uneven. 

Color  white,  colorless,  grayish,  green  to  black.  Streak  white,  grayish, 
greenish.  Luster  vitreous,  dull.  Transparent  to  opaque.  (See  p.  240.) 

In  basic  igneous  rocks;  in  crystalline  limestones  with  wernerite,  vesuvianite 
garnet. 

5  G.  3.1-3.3    ENSTATITE  (a  pyroxene),  MgSiO3;  FeO  up  to  12%. 

6  Struct. — Lamellar,  columnar,  fibrous,  compact;    prismatic  orthorhombic 
crystals  rare.     Cleavage  distinct,  two  directions  at  88°  and  92°  (110);  parting 
one  direction  (010),  bisecting  cleavage  angle;   brittle;  fracture  uneven. 

Color  grayish  white,  yellowish,  greenish,  to  olive-green  and  brown.  Streak 
white.  Luster  vitreous,  pearly;  submetallic,  bronzy  (bronzite).  Translucent 
to  opaque.  (See  pp.  240,  258.) 

In  basic  igneous  rocks  (gabbro,  peridotite)  and  serpentine. 

5  G.  3.0-3.2     Anthophyllite    (an    amphibole),    (Mg,Fe)SiO3;    sometimes    Al 

6  (Gedrite). 

Struct. — Lamellar,  columnar,  fibrous;  prismatic  orthorhombic  crystals 
rare.  Cleavage  two  directions  lengthwise  at  54f°  and  125^°  (110);  brittle; 
fracture  splintery;  fine  fibers  flexible  (asbestos). 

Color  gray,  clove-brown,  greenish  to  emerald.  Streak  white.  Luster 
vitreous,  pearly,  silky,  sometimes  metalloidal.  Translucent  to  opaque. 
(See  pp.  222,  238,  258.) 

In  schists  with  talc,  hornblende,  chlorite,  mica. 


SEC.  6]  PHYSICAL  TABLES  37 

H. 

6      G.  3.0-3.1     AMBLYGONITE,  Li(AlF)PO4;    Li2O10.1%;   often  Na  and  some- 
times OH. 

Struct. — Cleavable,  compact,  columnar;  triclinic  crystals  rare.  Cleavage 
conspicuous,  one  direction  (001),  less  distinct  in  another  plane  at  83°  and  97° 
to  this  (100);  brittle;  fracture  uneven. 

Color  white,  pale  gray,  green,  blue,  yellow,  brown.     Streak  white.     Luster 
vitreous;    pearly  on  (001).    Translucent   to  opaque.     Resembles  feldspars, 
but  heavier.     (See  p.  242.) 
|  Rare  in  pegmatite  with  tourmaline,  lepidolite,  apatite,  topaz. 

6      G.  2.5-2.6    ORTHOCLASE    (Potash  Feldspar),    KAlSi3O8;     K2O    16.9%; 

6|  often  Na. 

•  Struct. — Cleavable,  granular,  disseminated  grains;  prismatic  and  tabular 
monoclinic  crystals  and  twins  (Figs.  42  to  44).  Cleavage  distinct,  two  direc- 
tions at  90°  (010)  (001);  brittle;  fracture  conchoidal,  uneven. 

Color  white,  red,  gray,  green,  colorless.  Streak  white.  Luster  vitreous; 
often  pearly  on  cleavage.  Transparent  to  opaque.  (See  p.  238.) 

In  many  igneous  and  metamorphic  rocks;  in  veins  and  contacts;  with 
quartz,  other  feldspars,  mica,  hornblende,  pyroxene;  in  pegmatites  with  beryl, 
topaz,  tourmaline.  Adularia  is  transparent  or  opalescent  (moonstone).  Sani- 
dine  is  glassy,  often  transparent,  in  lavas.  Sunstone,  or  aventurine  feldspar, 
contains  brilliant  scales  of  hematite.  Perthite  and  microperthite  are  inter- 
laminated  orthoclase  and  albite.  Microcline  and  anorthoclase  are  triclinic 
and  have  cleavage  angles  not  quite  90°,  the  former  sometimes  bright  green 
(amazons tone,  amazonite),  the  latter  with  Na2O  up  to  8%.  Hyalophane,  with 
BaO  7-15%,  likewise  triclinic. 

6      G.  2.6-2.8    PLAGIOCLASE  (Soda-lime  and  Lime-soda  Feldspars),  ranging 
6£  from  NaAlSi3O8  (ab)  to  CaAl2Si2O8  (an),  often  some  K. 

Comp.         Sp.  G.  Comp.          Sp.  G. 

Albite  ab-ab6ani  2.62-2.64  Labradorite  ab^^-a^ans  2.70-2.72 
Oligoclase  ab6ani-ab3ani  2.65-2.67  Bytownite  abian3-abian6  2.73-2.75 
Andesine  ab3ani-abiani  2.68-2.69  Anorthite  abian<r-an  2.75-2.76 
Struct. — Lamellar,  granular,  disseminated;  small  triclinic  crystals  (Fig. 
46).  Cleavage  distinct,  two  directions  at  86°-86r  and  94-93i°  (001)  (010); 
often  striations  on  one  cleavage;  cleavage  often  curved;  brittle;  fracture 
uneven. 

Color  white,  colorless,  gray,  green,  bluish,  reddish;  sometimes  play  of 
colors — blue,  green,  yellow,  red.  Streak  white.  Luster  vitreous;  often 
pearly  on  cleavage.  Transparent  to  opaque,  sometimes  opalescent  (moon- 
stone), or  with  bright  reddish  or  yellowish  reflections  from  included  scales 
(aventurine  feldspar,  or  sunstone).  (See  p.  238.) 

In  igneous  rocks,  gneisses,  schists,  with  other  feldspars,  quartz,  mica, 
chlorite,  zeolites;  sometimes  in  veins. 

6  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  Al2SiO5,  or  (AlO)2SiO3. 

7  Struct. — Long  tabular  or  bladed  triclinic  crystals  without  terminations, 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  length- 


38  DETERMINATIVE  MINERALOGY  [SEC.  6 

H. 

wise  at  74°  and  106°  (100)  (010);  transverse  parting  (001)  common;  brittle; 
fracture  splintery. 

Color  blue,  white,  gray,  green,  nearly  black,  often  streaked.  Streak 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  pp.  256,  260.) 

Hardness  lengthwise  4-5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum. 

6  G.  3.1-3.2    SPODUMENE  (a  pyroxene),  LiAl(Si03)2;  Li2O  8.4%;  some  Na. 

7  Struct. — Cleavable,    columnar,    compact;    rough   prismatic   or   flattened 
monoclinic  crystals,  striated  lengthwise.     Cleavage  conspicuous,  two  direc- 
tions lengthwise  at  87°  and  93°  (110);    parting  sometimes  prominent,  one 
direction  (100),  bisecting  larger  cleavage  angle;    brittle;    fracture  uneven, 
splintery. 

Color  white,  gray,  yellowish;  emerald-green  (hiddenite);  pink  to  purple 
(kunzite).  Streak  white.  Luster  vitreous,  pearly.  Transparent  to  opaque. 
(See  p.  240,  242.) 

In  pegmatites  with  tourmaline,  lepidolite,  beryl,  amblygonite,  cassiterite. 


6£     G.  3.1-3.2    ANDALUSITE  (Chiastolite,  Made),  Al2SiO6,  or  Al(AlO)SiO4. 
1\        Struct. — Columnar,  granular,  disseminated;    rough  orthorhombic  prisms, 
nearly  square.     Cleavage  distinct,  two  directions  at  89°  and  91°  (110) ;  brittle; 
fracture  uneven. 

Color  white,  pink,  reddish  brown,  olive-green ;  sometimes  black  and  white 
cross  or  checkered  pattern  on  cross-fracture  (chiastolite,  or  made).  Streak 
white.  Luster  vitreous,  dull.  Translucent  to  opaque.  (See  p.  260.) 

In  slate,  schists,  and  gneiss;  with  sillimanite,  garnet,  biotite,  tourmaline, 
cordierite. 

n    G.  3.1  Lawsonite,  CaAl2(OH)4(SiO3)2. 

8          Struct. — Prismatic  or  tabular  orthorhombic  crystals;    lenticular  plates. 
Cleavage  perfect,  two  directions  at  90°  (010)  (001);  brittle;  fracture  uneven. 
Color  pale  blue,  bluish  gray,  colorless;  white  or  grayish  spots  due  to  altera- 
tion.    Streak    white.    Luster    virteous,    greasy.    Transparent    to    opaque. 
(See  p.  244.) 

In  schists  with  glaucophane,  actinolite,  margarite,  epidote,  garnet. 

81     G.  3.5-3.8    CHRYSOBERYL  (Cymophane),  G1A12O4. 

Struct. — Tabular  orthorhombic  crystals,  heart-shaped  or  pseudohexagonal 
twins,  disseminated  plates.  Cleavage  two  directions  at  60°  and  120°  (Ollh 
brittle;  fracture  uneven,  conchoidal. 

Color  yellowish  green,  deep  green,  greenish  white,  greenish  brown,  yellow. 
Alexandrite,  the  deep  green  variety,  is  red  by  gas  or  lamp  light,  cat's  eye  is 
yellowish  green,  opalescent.  Streak  white.  Luster  vitreous,  greasy.  Trans- 
parent to  translucent.  (See  p.  260.) 

In  granite,  gneiss,  mica  schist,  placers;  with  beryl,  garnet,  tourmaline, 
sillimanite. 


SEC.  7]  PHYSICAL  TABLES  39 


SECTION  7 

Streak  chalk-white,  colorless,  or  pale  colored;    mineral  white, 
colorless,  or  pale  colored;  distinct  cleavage  three  or  more  directions. 

H. 

1^     G.  2.3-2.4    GYPSUM  (Selenite,  Alabaster,  Satin  Spar),  CaSO4-2H2O. 
2          Struct. — Granular,  foliated,  fibrous,  earthy;   diamond-shaped  monoclinic 
crystals  with  beveled  edges  (Figs.  38,  39).     Cleavage  perfect,  one  direction 
(010);    two  others  less  conspicuous  (111)  (100)  at  90°,  66°,  114°;    brittle; 
thin  flakes  flexible;  fracture  conchoidal,  splintery. 

Color  white,  colorless,  gray,  yellow,  red.  Streak  white.  Luster  vitreous; 
pearly  on  (010);  silky.  Transparent  to  opaque.  (See  pp.  224,  226.) 

Beds  and  masses  with  limestone,  shale,  clay,  rock  salt;  near  volcanic  vents; 
with  anhydrite,  celestite,  sulphur,  calcite,  aragonite. 

2      G.  2.1-2.6    HALITE  (Common  Salt,  Rock  Salt),  NaCl;   Na  60.6%;   often 
48i  Ca  and  Mg. 

Struct. — Granular,  cleavable,  compact;  isometric  crystals  (cubes,  Fig.  5); 
Cleavage  distinct,  three  directions  at  90°  (100);  brittle;  fracture  conchoidal. 
Color  white,  colorless,  grayish,  reddish,  bluish.     Streak  white.    Luster 
vitreous.     Transparent  to  translucent.     Taste  salty.     (See  p.  224.) 

Beds  in  sedimentary  strata  with  gypsum,  anhydrite,  sylvite,  calcite,  clay, 
sand;  in  dry  lakes;  in  brines.  (Compare  cryolite,  p.  49.) 

2  G.  1.9-2.0    STLVITE,  KC1;  K  52.4%;  sometimes  Na. 

2|  Struct. — Granular,  compact;  isometric  crystals  (cubes,  Fig.  5) .  Cleavage 
distinct,  three  directions  at  90°  (100);  brittle;  fracture  conchoidal. 

Color  white,  colorless,  grayish,  bluish,  reddish.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  Taste  salty,  bitter;  becomes  damp 
in  moist  air.  (See  p.  224.) 

In  salt  deposits;  with  halite,  kainite,  carnallite. 

2|    G.  2.0-2.2    KAINITE,  KMgClSO4-3H2O;  K  18.9%. 

3  Struct. — Compact,  fine  granular;    rarely  tabular  or  prismatic  monoclinic 
crystals.     Cleavage  distinct,  three  directions  at  39£°,  101°,  140£°  (100)  (110); 
brittle;  fracture  uneven. 

Color  white,  colorless,  reddish.     Streak  white.    Luster  vitreous.     Trans- 
parent to  translucent.     Taste  salty,  bitter,  astringent.     (See  p.  224.) 
In  beds  with  halite  sylvite,  gypsum,  anhydrite. 

2?    G.  4.3-4.6    BARITE  (Barytes,  Heavy  Spar),  BaS04;  sometimes  Ca  and  Sr. 
85        Struct. — Tabular  and  prismatic  orthorhombic  crystals,  divergent  groups; 
compact,  lamellar,  fibrous.     Cleavage  distinct,  three  directions  at  78|°,  90°, 
and  lOlf0  (001)  (110);  brittle;  fracture  uneven. 

Color  white,  colorless,  light  shades  of  yellow,  brown,  red,  blue.  Streak 
white.  Luster  vitreous,  pearly.  Transparent  to  opaque.  (See  p.  226.) 

In  veins  with  galena,  sphalerite,  fluorite,  chalcopyrite;  in  limestones  and 
residual  clays  with  oxides  of  manganese  and  iron. 


40  DETERMINATIVE   MINERALOGY  [SEC.  7 

H. 

3      G.  2.7  CALCITE  (Calc  Spar),  CaCO3;  often  Mg,  Fe,  Mn,  sometimes  Pb. 

Struct. — Hexagonal-rhombohedral  crystals,  prismatic,  scalenohedral, 
rhombohedral,  tabular,  or  acicular  in  habit  (Figs.  52  to  57);  rarely  twins; 
cleavable,  granular,  stalactitic,  oolitic,  earthy.  Cleavage  perfect,  three  direc- 
tions at  75°  and  105°  (1011);  brittle;  fracture  conchodial,  seldom  observed. 

Color  white,  colorless,  pale  shades  of  gray,  yellow,  red,  green,  blue,  violet; 
brown  to  black  when  impure.  Streak  white.  Luster  vitreous,  dull.  Trans- 
parent to  opaque.  (See  p.  246.) 

Chief  constituent  of  limestone,  marble,  chalk,  calcareous  marl;  in  veins 
with  metallic  ores,  quartz,  pyrite,  zeolites.  Dog  tooth  spar  and  nail  head  spar 
are  suggestive  crystal  habits;  Fontainebleau  limestone,  crystals  containing 
much  sand;  satin  spar,  fibrous,  silky;  Iceland  spar,  transparent,  suitable  for 
optical  uses;  chalk,  soft,  white,  yellowish,  earthy;  calcareous  marl,  soft,  earthy, 
with  clay;  stalactites  and  stalagmites,  cave  deposits;  cole  sinter,  calc  tufa, 
travertine,  deposits  of  springs  or  streams,  porous,  cavernous;  thinolite,  layers 
of  yellow  to  brown  cellular  and  skeleton  crystals  forming  extensive  tufa  in  dry 
lakes  (N.  W.  Nevada),  apparently  tetragonal  pseudomorphs. 

• 
3      G.  6.1-6.4    ANGLESITE  (Lead  Vitriol),  PbS04;  Pb  68.3%. 

Struct. — Orthorhombic  crystals;  granular,  compact.  Cleavage  not  con- 
spicuous, three  directions  at  76°,  90°,  and  104°  (001)  (110);  brittle;  fracture 
conchoidal. 

Color  white,  colorless,  gray,  brown,  green.  Streak  white.  Luster  ada- 
mantine, vitreous.  Transparent  to  translucent.  (See  p.  214.) 

In  oxidized  parts  of  ore  deposits  with  lead,  zinc,  and  iron  minerals. 

3      G.  2.9-3.0    ANHYDRITE  (Anhydrous  Gypsum),  CaSO4. 
3%        Struct. — Granular,    compact,    fibrous,    cleavable;     rarely   orthorhombic 
crystals.     Cleavage  distinct,  three  directions  at  90°  (001)  (100)  (010);  brittle; 
fracture  conchoidal. 

Color  white,  grayish,  bluish,  reddish  to  brick-red.     Streak  white  to  grayish. 
Luster  vitreous;   pearly  on  (001).     Translucent  to  opaque.     (See  p.  226.) 
In  limestones,  shales,  salt  deposits;  with  halite,  gypsum,  calcite. 

3      G.  3.9-4.0    CELESTITE,  SrSO4;  sometimes  Ca  and  Ba. 
3|        Struct. — Tabular  or  prismatic  orthorhombic  crystals  (Fig.  37);    fibrous, 
cleavable,  rarely  granular.     Cleavage  distinct,  three  directions  at  76°,  90°, 
and  104°  (001)  (110);  brittle;  fracture  uneven. 

Color  white,  colorless,  bluish,  reddish.  Streak  white.  Luster  vitreous, 
pearly.  Transparent  to  translucent.  (See  p.  226.) 

In  limestones  and  shales  with  gypsum,  halite,  sulphur,  galena,  aragonite. 


G.  2.8-2.9    DOLOMITE,  CaMg(CO3)2;  often  Fe,  Mn;  much  iron,  Ankerite. 
Struct. — Granular,  cleavable,  compact;  hexagonal-rhombohedral  crystals, 
faces  often  curved  (pearl  spar).     Cleavage  perfect,  three  directions  at  74° 
and  106°  (lOll);  brittle;  fracture  conchoidal,  uneven. 


SEC.  7]  PHYSICAL  TABLES  41 

• 

H. 

Color  white,  colorless,  gray,  red,  green,  brown,  black.  Streak  white. 
Luster  vitreous,  pearly.  Transparent  to  opaque.  (See  p.  246.) 

Extensive  strata  as  dolomitic  limestone  and  marble;  gangue  with  ores  of 
lead,  zinc,  etc.;  with  serpentine,  talc,  gypsum,  and  ordinary  limestone. 

3^  G.  3.8-3.9  SIDERITE  (Spathic  Iron,  ChalyUte,  Clay  Ironstone,  Black 
4  Band  Ore),  FeCO3;  Fe48.3%. 

Struct. — Granular,  cleavable,  compact;  hexagonal-rhombohedral  crystals, 
curved  and  saddle-shaped  common.  Cleavage  perfect,  three  directions  at 
73°  and  107°  (lOll);  brittle;  fracture  uneven. 

Color  gray,  yellow,  brown,  black,  sometimes  white.  Streak  white,  pale 
yellow.  Luster  vitreous,  pearly,  dull.  Translucent  to  opaque.  (See  pp  .218, 
248.) 

In  veins  with  silver  minerals,  pyrite  and  other  sulphides,  cryolite;  beds 
and  concretions  in  limestone,  shale,  and  coal. 

3}    G.  2.9-3.0    ARAGONITE  (Flos  Ferri),  CaCO3;  sometimes  Sr  and  Pb. 
4          Struct. — Chisel-  or  spear-shaped  orthorhombic  crystals,  pseudohexagonal 
prisms;   acicular,  columnar,  stalactitic,  coral-like.     Cleavage  three  directions 
at  64°,  90°,  and  116°;  (110)  (010);  brittle;  fracture  conchoidal. 

Color  white,  gray,  yellow,  pale  green,  violet.  Streak  white.  Luster 
vitreous,  resinous.  Transparent  to  translucent.  (See  p.  246.) 

In  gypsum  beds,  basalt,  serpentine,  beds  of  limonite  and  siderite;  with 
celestite,  sulphur,  metallic  sulphides,  zeolites;  constitutes  some  shells  (pearly 
layers  of  many)  and  some  coral. 

3£  G.  3.9-4.1  SPHALERITE  (Blende,  Zinc  Blende,  Jack,  Black  Jack,  Rosin 
4  Jack),  ZnS;  Zn  67%;  may  be  replaced  by  Fe  up  to  18%. 

Struct. — Cleavable  masses,  granular,  compact,  botryoidal;  rounded 
isometric-tetrahedral  crystals.  Cleavage  pronounced,  six  directions  at  60°, 
90°,  and  120°  (110);  brittle;  fracture  conchoidal. 

Color  yellow,  brown,  red,  green,  black;  rarely  white  or  pale  gray  (cleio- 
phane).  Streak  white,  light  to  dark  brown.  Luster  resinous,  adamantine, 
submetallic.  Transparent  to  opaque.  (See  pp.  200,  228,  250.) 

Ore  deposits  and  veins  with  galena,  pyrite,  chalcopyrite,  fluorite,  barite; 
also  in  limestone. 

3J    G.  2.2-2.3    LAUMONTITE  (a  zeolite),  H4Ca(AlO)2(SiO3)4-2H2O. 

4          Struct. — Radial,  divergent,  columnar;   prismatic  monoclinic  crystals  with 

oblique  terminations.     Cleavage  three  directions  lengthwise  at  86°,  94°,  and 

137°  (110)  (010);  brittle,  friable;  fracture  uneven,  earthy. 

Color  white,  yellowish,  grayish,  reddish.     Streak  white.     Luster  vitreous, 

pearly.     Transparent  to  opaque.     Becomes  dull,  opaque,  and  powdery  on 

exposure.     (See  p.  230.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;    in  metalliferous 

veins;  with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite, 

quartz,  epidote,  pyrite,  chalcopyrite,  chlorite. 


42  DETERMINATIVE  MINERALOGY  [SEC.  7 

H. 

3|     G.  3.4-3.6    RHODOCHROSITE  (Dialogite),  MnCO3;    Mn  47.8%;   some- 

4£  times  Fe,  Ca,  Mg. 

Struct. — Cleavable,  granular,  compact,  botryoidal,  incrusting;  hexagonal- 
rhombohedral  crystals  rare,  commonly  with  curved  faces.  Cleavage  conspicu- 
ous, three  directions  at  73°  and  107°  (lOll);  brittle;  fracture  uneven. 

Color  reddish  white,  rose-red,  dark  red,  brown;  brown  to  black  on  exposure. 
Streak  white.  Luster  vitreous,  pearly.  Transparent  to  translucent.  (See 
p.  248.) 

In  veins  with  other  manganese  minerals,  ores  of  silver,  lead,  and  copper; 
pyrite. 

3£     G.  3.0-3.1     MAGNESITE,   MgCO3;    sometimes  much  Fe   (Breunnerite); 
±\  also  Mn. 

Struct. — Compact  like  unglazed  porcelain,  granular,  cleavable;  rarely 
hexagonal-rhombohedral  crystals.  Cleavage  conspicuous,  three  directions 
at  72|°  and  1075°  (lOll);  tough  to  brittle;  fracture  conchoidal. 

Color  white,  yellowish,  grayish,  brown.  Streak  white.  Luster  vitreous, 
dull.  Transparent  to  opaque.  (See  p.  248.) 

Forming  extensive  beds;  disseminated  in  talc  and  chlorite  schists;  veins 
in  serpentine,  dolomite,  limestone;  with  gypsum. 

4      G.  3.0-3.2     FLUORITE  (Fluor  Spar,  Blue  John),  CaF2;   F  48.9%;   some- 
times Cl. 

Struct. — Isometric  crystals  (cubes,  penetration  twins,  Figs.  5, 12);  cleavable 
masses,  granular,  columnar.  Cleavage  perfect,  four  directions  at  70J0  and 
109£°  (HI);  brittle;  fracture  uneven. 

Color  violet,  blue,  green,  yellow,  colorless,  brown.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  (See  p.  226.) 

Common  in  veins  and  contacts  with  galena,  sphalerite,  calcite,  barite, 
cassiterite,  apatite,  topaz,  lepidolite;  in  limestones;  rare  in  igneous  rocks. 

4  G.  2.0-2.2    CHABAZITE  (azeolite),  CaAl2(SiO3)4-6H2O;  oftenK,  Na,  Ba, 

5  Sr. 

Struct. — Hexagonal-rhombohedral  crystals  (cube-like  rhombohedrons), 
also  modified  forms,  twins;  compact.  Cleavage  distinct,  three  directions  at 
85°  and  95°  (lOll);  brittle;  fracture  uneven. 

Color  white,  yellow,  flesh-red.  Streak  white.  Luster  vitreous.  Trans- 
parent to  translucent.  (See  p.  234.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite, 
quartz,  epidote,  pyrite,  chalcopyrite,  chlorite. 

4  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  Al2SiO6,  or  (A10)2Si03. 

5  Struct. — Long  tabular  or  bladed  triclinic  crystals  without  terminations, 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  length- 
wise at  74°  and  106°  (100)  (010);  transverse  parting  (001)  common;  brittle; 
fracture  splintery. 


SEC.  7]  PHYSICAL  TABLES  43 

H. 

Color  blue,  white,  gray,  green,  nearly  black;  often  streaked.  Streak 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  pp.  256,  260.) 

Hardness  lengthwise  4—5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum. 

4|  G.  5.9-6.1  SCHEELITE,  CaWO4;  WO380.6%;  some  Mo;  sometimes  Cu 
5  (Cuproscheelite) . 

Struct. — Small  pyramidal  tetragonal  crystals  resembling  octahedrons, 
sometimes  tabular;  incrusting,  granular,  compact.  Cleavage  distinct,  four 
directions  at  49|°,  80°,  100°,  and  130|°  (111);  brittle;  fracture  conchoidal, 
uneven. 

Color  white,  yellow,  brownish,  greenish,  reddish.  Streak  white  to  yellow- 
ish. Luster  greasy,  adamantine.  Transparent  to  translucent.  (See  pp. 
234,  254,  258.) 

In  veins  and  contacts  with  quartz,  cassiterite,  topaz,  fluorite,  apatite, 
molybdenite. 

5  G.  4.3-4.5  SMITHSONITE  (Dry  Bone;  Calamine,  hi  England),  ZnCO3; 
Zn52.1%. 

Struct. — Mammillary,  stalactitic,  incrusting,  cellular  (dry  bone);  rarely 
small  hexagonal-rhombohedral  crystals.  Cleavage  distinct,  three  directions 
at  72°  and  108°  (lOll);  brittle;  fracture  uneven,  splintery. 

Color  white,  grayish,  colorless,  greenish,  blue,  pink,  brown.  Streak  white. 
Luster  vitreous,  adamantine,  pearly,  dull.  Transparent  to  opaque.  (See 
p.  248.) 

In  oxidized  zinc  ores,  usually  in  limestone  or  clay,  with  smithsonite,  cerusite, 
anglesite,  galena,  sphalerite,  calcite,  limonite. 

5  G.  3.2-3.6    DIOPSIDE  (Malacolite,  a  pyroxene),  CaMg(Si03)2;   some  Fe. 

6  Struct. — Prismatic    monoclinic    (pseudotetragonal)    crystals,    stout,    ter- 
minated (Figs.  40,  41);  lamellar,  granular,  compact.     Cleavage  two  directions 
lengthwise  at  87°  and  93°  (110)  sometimes  distinct;  often  conspicuous  trans- 
verse parting  (001);  brittle;  fracture  uneven. 

Color  white,  colorless,  grayish,  green  to  black.  Streak  white,  grayish, 
greenish.  Luster  vitreous,  dull.  Transparent  to  opaque.  (See  p.  240.) 

In  basic  igneous  rocks;  in  crystalline  limestones  with  wernerite,  vesuvianite, 
garnet. 

5  G.  3.1-3.3    ENSTATITE  (a  pyroxene),  MgSi03;  FeO  up  to  12%. 

6  Struct. — Lamellar,  columnar,  fibrous,  compact;    prismatic  orthorhombic 
crystals  rare.     Cleavage  distinct,  two  directions  at  88°  and  92°  (110);  parting 
one  direction  (010),  bisecting  cleavage  angle;  brittle;  fracture  uneven. 

Color  grayish  white,  yellowish,  greenish,  to  olive-green  and  brown.  Streak 
white.  Luster  vitreous,  pearly;  submetallic,  bronzy  (bronzite).  Translucent 
to  opaque.  (See  pp.  240,  258.) 

In  basic  igneous  rocks  (gabbro,  peridotite)  and  serpentine. 


44  DETERMINATIVE  MINERALOGY  [SBC.  7 

H. 

5  G.  2.5-2.6    NEPHELITE  (Nepheline,  Elaeolite;  a  feldspathoid),  NaAlSiO4; 

6  also  K  (up  to  7%  K2O). 

Struct. — Compact,  disseminated  grains;  small  hexagonal  crystals  rare. 
Cleavage  distinct,  three  directions  at  60°  and  120°  (1010);  brittle;  fracture 
conchoidal,  uneven. 

Color  reddish,  brownish,  greenish,  gray,  white,  colorless.  Streak  white. 
Luster  greasy,  vitreous.  Transparent  to  opaque.  (See  p.  232.) 

In  lavas  and  granular  igneous  rocks  with  feldspars,  sodalite,  cancrinite, 
biotite,  zircon,  corundum;  not  with  quartz. 

5  G.  3.9-4.2    WILLEMITE,  Zn2SiO4;   Zn  58%;    may  contain  Mn   (Troostite); 

6  some  Fe. 

Struct. — Compact,  granular,  disseminated  grains;  prismatic  hexagonal- 
rhombohedral  crystals  rare.  Cleavage  distinct,  three  directions  at  60°  and 
120°  (1120);  brittle;  fracture  conchoidal,  uneven. 

Color  yellow,  green,  red,  brown,  white.  Streak  white.  Luster  vitreous. 
Transparent  to  opaque.  (See  pp.  232,  252.) 

In  crystalline  limestone  with  franklinite,  zincite,  rhodonite. 

5  G. "2.6-2.8    WERNERiTE(-ScapoZiie),  n(Ca4AlcSi6O25)-m(Na4Al3Si9O24Cl). 

6  Struct. — Stout  prismatic  tetragonal  crystals;    compact,  fibrous,  granular. 
Cleavage  three  directions  lengthwise  at  45°  and  90°  (100)  (110),  not  con- 
spicuous; brittle;  fracture  conchoidal,  uneven. 

Color  white,  gray,  greenish,  bluish,  reddish.  Streak  white.  Luster 
vitreous,  greasy.  Translucent  to  opaque.  (See  pp.  234,  244.) 

In  crystalline  limestones  and  schists  with  pyroxenes,  amphiboles,  apatite, 
garnet,  biotite. 

5  G.  2.4-2.5    CANCRINITE  (a  feldspathoid),  H.Na«Ca(NaCO,).Al8(SiO4).. 

6  Struct. — Compact,  lamellar,  columnar,  disseminated;  prismatic  hexagonal 
crystals  rare.     Cleavage  distinct,  three  directions  at  60°  and  120°    (10lO); 
brittle;  fracture  uneven. 

Color  white,  gray,  yellow,  green,  blue,  reddish.  Streak  white.  Luster 
vitreous,  greasy,  pearly.  Transparent  to  translucent.  (See  p.  230.) 

In  granular  igneous  rocks  with  nephelite,  sodalite,  biotite,  feldspars, 
titanite;  not  with  quartz. 

6  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  Al2SiO8,  or  (AlO)2SiO3. 

7  Struct. — Long  tabular  or  bladed  triclinic  crystals  without  terminations, 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  length- 
wise at  74°  and  106°  (100)  (010);  transverse  parting  (001)  common;  brittle; 
fracture  splintery. 

Color  blue,  white,  gray,  green,  nearly  black,  often  streaked.  Streak 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  pp.  256,  260.) 

Hardness  lengthwise  4-5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum. 


SEC.  7]  PHYSICAL  TABLES  45 

H. 

6J     G.  3.5-3.7     GROSSULARITE  (Essonite,  Hessonite,  Cinnamon  Stone,  a  garnet), 

7J  CaaAls(SiO4)»;  often  some  Fe,  Mg,  Mn. 

Struct. — Isometric  crystals  (dodecahedrons,  trapezohedrons,  Figs.  3,  7); 
granular,  disseminated,  lamellar,  sand.  Cleavage  none;  parting,  sometimes 
distinct,  six  directions  at  60°,  90°,  and  120°  (110);  brittle;  fracture  conchoidal, 
uneven. 

Color  white,  pink,  yellow,  brownish,  pale  green.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  (See  p.  244.) 

In  limestone  contacts  with  wollastonite,  vesuvianite,  diopside,  scapolite. 

7|    G.  2.9-3.0    PHENACITE,  Gl2Si<X 

8  Struct. — Hexagonal-rhombohedral  crystals,  prismatic,  lenticular;     Cleav- 
age distinct,  three  directions  at  60°  and  120°  (1120);   brittle;   fracture  con- 
choidal. 

Color  colorless,  wine  yellow,  rose  red,  brown.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  (See  p.  264.) 

In  pegmatite  and  metamorphic  rocks  with  quartz,  topaz,  beryl,  micro- 
cline,  chrysoberyl. 

9  G.  3.9-4.1     CORUNDUM  (Adamantine  Spar),  A12O3. 

Struct. — Rough  hexagonal-rhombohedral  crystals,  prismatic,  pyramidal, 
tabular,  tapering  (barrel-shaped),  often  striated;  lamellar,  granular,  compact. 
Cleavage  none;  often  conspicuous  parting,  three  directions  at  86°  and  94° 
(1011);  sometimes  transverse  parting  (0001);  brittle,  tough  when  compact; 
fracture  uneven,  conchoidal. 

Color  white,  gray,  brown  to  black;  deep  red  (ruby)',  blue  (sapphire); 
black  from  admixture  of  magnetite,  hematite,  or  spinel  (emery).  Streak 
white.  Luster  vitreous,  adamantine.  Transparent  to  opaque.  (See  p.  260.) 

In  peridotite,  gneiss,  schist,  syenite,  crystalline  limestone;  with  olivine, 
chlorite,  serpentine,  magnetite,  spinel,  vermiculite;  cyanite,  diaspore,  mus- 
covite. 

10  G.  3.5  DIAMOND  (Carbon),  C. 

Struct. — Isometric  crystals  (octahedron,  hexoctahedron,  Figs.  1,  4), 
usually  with  curved  surfaces;  rounded  and  irregular  grains,  pebbles,  often 
with  radial  structure.  Cleavage  distinct,  four  directions  at  70£°  and  1095° 
(111);  brittle;  fracture  conchoidal. 

Color  white,  colorless;  pale  shades  of  yellow,  red,  orange,  green,  blue, 
brown;  occasionally  black.  Streak  white.  Luster  adamantine,  greasy. 
Transparent  to  opaque.  Bort,  rough  rounded  masses  with  radial  or  con- 
fused crystalline  structure,  without  distinct  cleavage;  grayish  to  black; 
sp.  g.  3.5.  Carbonado,  or  black  diamond,  granular  to  compact,  without 
cleavage;  sp.  g.  3.1-3.3.  (See  p.  264.) 

In  peridotite  or  serpentine;  in  sands,  gravels,  quartzite;  with  pyrope, 
magnetite,  chromite,  zircon,  gold. 


46  DETERMINATIVE  MINERALOGY  [SEC.  8 


SECTION  8 

Streak  chalk-white,  colorless,  or  pale  colored;    mineral  white, 
colorless,  or  pale  colored;   no  distinct  cleavage. 

H. 

0  G.  2.6  KAOLINITE  (Kaolin,  China  Clay),  H4Al2Si2O9. 

1  Earthy,  powdery;  white,  gray,  yellowish,  reddish;  commonly  soapy  feel 
and  plastic  when  wet.     (See  p.  47.) 

0  G.  2.4-2.6    BAUXITE    (Beauxite),    mixture   of   A1O-OH   and   A1(OH)3; 

1  Al  30-40%. 

Clay-like,  powdery,  pisolitic;   white,  gray,  yellowish,  reddish.     A  mark 
made  with  heavy  pressure  on  glass  not  easily  rubbed  off.     (See  p.  47.) 

0  G.  2.7  CHALK  (Marl,  earthy,  impure),  CaC03;  a  variety  of  calcite. 

1  Powdery,  clay-like,  earthy;   white,  gray,  yellowish;   harsh  feel.     (See  p. 
40.) 

0  G.  2.3-2.4    GYPSITE  (earthy  gypsum),  CaSO4-2H2O. 

1  Powdery,  clay-like,  earthy;  white,  gray  yellowish.     (See  Gypsum,  p.  30.) 

0  G.  2.1-2.2    TRIPOLITE  (Tripoli,  Diatomaceous  Earth,  Infusorial  Earth, 

1  Diatomite),  SiO2-»H2O;   the  composition  of  opal. 
Powdery,  earthy;  a  chalk-like  opal;  apparently  soft,  but  particles  scratch 

glass;  harsh  feel.     White,  gray,  yellowish.     (See  p.  48.) 

0  G.  1.7-1.8    EPSOMITE  (Epsom  Salt),  MgSO4-7H2O. 

1  Fibrous  efflorescence,  earthy  powder;  colorless,  white,  gray.     Bitter  saline 
taste.     (See  p.  49.) 


0  G.  1.6-1.7    ULEXITE  (Boronatrocalcite,  Natronborocakite),  NaCaB509-8H2O. 

1  Struct. — Fine  fibrous  masses  ("  cotton  balls  "),  easily  pulverized  (mono- 
clinic). 

Color  white.    Streak  white.    Luster  silky.    Translucent.     (See  p.  228.) 
In  dry  lakes  or  about  salt  lakes  with  halite,  gypsum,  borax,  glauberite. 

1      G.  5.5-5.6    CERARGTRITE  (Horn  Silver),  AgCl;  Ag  75.3%;  sometimes  Hg, 
1^        Struct. — Wax-like  crusts,  stalactitic,  dendritic;  isometric  (cubic)  crystals 
rare.     Cleavage  none;  highly  sectile;  fracture  conchoidal. 

Color  pearly  gray,  greenish,  colorless;  turns  violet,  brown,  to  black  on 
exposure  to  light.  Streak  white,  grayish,  shiny.  Luster  waxy,  greasy,  resin- 
ous. Transparent  to  translucent.  (See  p.  216.) 

In  veins  with  other  silver,   minerals,  calcitebarite,  limonite. 


SEC.  8]  PHYSICAL  TABLES  47 

H. 

1      G.  2.5-3.2    ASBESTOS:    Two   varieties:    (1)  Chrysotile   (fibrous    serpen- 
3  tine),     H4Mg3Si2O9;    (2)  Fibrous    amphiboles:    anthophyl- 

lite,     (Mg,Fe)SiO3;    tremolite,    CaMg3(SiO3)4;    actinolite, 
Ca(Mg,Fe)3(SiO3)4;  crocidolite,    NaFe"Fe"'(SiO3)3. 
Struct. — Parallel  flexible  fibers;   felted  aggregates  (mountain  paper,  moun- 
tain cork,  mountain  leather,  mountain  wood) . 

Color  white,  gray,  yellowish;  also  lavender-blue  (crocidolite).  Luster 
silky,  dull.  Translucent  to  opaque.  (See  pp.  36,  62,  110,  122,  148.) 

Chrysotile  is  chiefly  short  cross-fiber,  perpendicular  to  walls  of  veins  in 
serpentine,  fibers  fine  silky,  very  flexible,  tough;  some  slip-fiber  parallel  to 
walls.  Amphibole  asbestos,  chiefly  long  fiber  parallel  to  walls  of  veins  in  perido- 
tite  or  pyroxenite,  or  chief  constituent  of  latter,  is  dull,  coarser  fiber,  little 
strength  or  toughness.  The  crocidolite  variety  is  exceptional  in  most  of  these 
respects,  being  fine  silky  and  tough, 

1  G.  1.6  CARNALLITE,  KMgCl3-6H2O;  KC1  26.8%. 

2  Struct. — Granular,   compact;    orthorhombic   (pseudohexagonal)    crystals 
rare.     Cleavage  indistinct;   brittle;   fracture  conchoidal. 

Color  white,  grayish,  brownish,  reddish.  Streak  white.  Luster  vitreous, 
greasy.  Transparent  to  translucent.  Bitter  taste;  absorbs  moisture. 
(See  p.  224.) 

With  halite,  kieserite,  sylvite,  boracite,  anhydrite. 

1  G.  6.4-6.5     Calomel  (Horn  Quicksilver),  H&Cl,;  Hg  84.9%. 

2  Struct. — Coatings;  small  tetragonal  crystals,  tabular,  pyramidal.     Cleav- 
age indistinct,  two  directions  (100)  at  90°;  sectile;  fracture  conchoidal. 

Color  white,  gray,  yellowish  to  brown.     Streak  white,  gray,  yellowish. 
Luster  adamantine.     Translucent  to  opaque.     (See  p.  212.) 
In  veins  with  cinnabar  and  mercury. 

1      G.  2.4-2.6    KAOLINITE  (Kaolin,  China  Clay,  Porcelain  Clay),  H4Al2Si2O9. 

2%        Struct. — Friable,   clay-like,   compact;    minute  scaly  monoclinic  crystals 
(pseudohexagonal  or  pseudorthorhombic)  rare;   brittle;  fracture  earthy. 

Color  white,  gray,  yellowish,  reddish.  Streak  white.  Luster  dull,  pearly. 
Opaque  to  translucent.  Generally  plastic  when  moist.  (See  p.  256.) 

With  quartz,  feldspar;  largely  from  decomposition  of  latter;  chief  con- 
stituent of  most  clay.  H  alloy  site,  amorphous  variety,  little  or  no  plasticity; 
translucent  to  transparent  in  water;  infusible.  Bentonile,  amorphous  variety, 
brittle;  soapy  feel;  very  plastic  when  wet;  absorbs  three  times  its  weight 
and  seven  times  its  volume  of  water;  finally  a  glue-like  paste.  Fuller's  earth, 
absorbent  variety,  decolorizes  oils  and  other  liquids. 

1      G.  2.4-2.6    BAUXITE  (Beauxite),  mixture  of  colloidal  A1O-OH  (Diaspore) 

3  and  Al(OH),  (Gibbsite);  often  Fe,  Si,  Ca,  Mg;  Al  30-40%. 
Struct. — Amorphous,  earthy,  pisolitic,  oolitic;  brittle. 

Color  white,  gray,  yellow,  red.  Streak  white.  Luster  dull.  Opaque. 
A  mark  made  with  heavy  pressure  on  glass  not  easily  rubbed  off.  (See  p. 
256.) 

Nodules  and  beds  in  clay  or  limestone,  with  iron  oxides. 


48  DETERMINATIVE  MINERALOGY  [Sue.  8 

H. 

1  G.  2.1-2.2    TRIPOLITE  (Tripoli,   Infusorial  Earth,   Diaiomite,   Diatoma- 
3  ceous  Earth),  SiO2-nH2O;  the  composition  of  opal. 

Struct. — Amorphous,  porous,  earthy,  chalk-like;  particles  scratch  glass; 
harsh  feel;  not  plastic  when  wet 

Color  white,  gray,  yellowish.  Streak  white.  Luster  dull.  Opaque. 
(See  p.  54.) 

Associated  and  in  part  mingled  with  clay,  sand,  peat. 

1|    G.  2.2-2.3    SODA  NITER  (Chile  Saltpeter),  NaNO3;   N2O5  63.5%. 

2  Struct. — Granular,  crusts,  efflorescences;    rarely  hexagonal-rhombohedral 
crystals,  like  calcite.     Cleavage  distinct,  three  directions  at  73-2°  and  106|° 
(1011);  brittle,  somewhat  sectile;  fracture  conchoidal. 

Color  white,  colorless,  grayish,  yellowish,  brownish.  Streak  white. 
Luster  vitreous.  Transparent  to  translucent.  Taste  cool,  salty;  becomes 
damp  in  moist  air.  (See  p.  224.) 

Extensive  deposits  in  some  arid  districts  (Chile);  with  gypsum,  sand, 
clay,  guano. 

1|    G.  1.4-1.5    MIRABILITE  (Glauber  Salt),  Na2SO4  •  10H2O. 
2          Struct. — Mealy  efflorescences,  fibrous  crusts,  powder;  monoclinic  crystals 
rare.     Cleavage  perfect,  one  direction  (100);   brittle;   fracture  conchoidal. 

Color  white,  colorless,  yellowish.     Streak  white.    Luster  vitreous.     Trans- 
parent to  opaque.     Taste  cool,  saline.     (See  p.  224.) 
In  dry  lakes  with  halite,  gypsum,  clay,  marl. 

1J    G.  2.0-2.1    SULPHUR. (Brimstone),  S;  traces  of  Te,  Se,  As. 
2 §        Struct. — Granular,  fibrous,   compact,  earthy;    reniform,   stalactitic;    in- 
crusting;  orthorhombic  crystals,  pyramidal  (Figs.  34,  35),  or  tabular.     Cleav- 
age indistinct;  brittle;  fracture  conchoidal. 

Color  yellow,  greenish  or  reddish  yellow,  brown,  gray.  Streak  white, 
pale  yellow.  Luster  resinous,  greasy,  adamantine.  Transparent  to  translu- 
cent. (See  p.  212.) 

In  beds  with  gypsum;  about  vents  of  volcanoes  and  fumaroles;  in  oxi- 
dized parts  of  sulphide  ores;  with  celestite,  gypsum,  calcite,  aragonite. 

2      G.  1.9  MELANTERITE  (Copperas,  Green  Vitriol),  FeSO4-7H2O. 

Struct. — Capillary,  fibrous,  compact,  stalactitic,  concretionary,  powdery; 
monoclinic  crystals  rare.  Cleavage  inconspicuous,  one  direction  crosswise 
(001);  brittle;  fracture  conchoidal,  earthy. 

Color  green,  yellowish  green,  white;  dull  yellowish  white  on  exposure. 
Streak  white.  Luster  vitreous,  dull.  Transparent  to  translucent.  Sweet 
astringent  taste.  (See  p.  218.) 

Oxidation  product  of  iron  sulphide  minerals — marcasite,  pyrite,  chal- 
copyrite,  pyrrhotite,  etc. 

2      G.  2.1-2.2     NITER  (Saltpeter),  KNO3;   K2O  46.5%. 

Struct. — Crusts,  efflorescences,  needle-like  aggregates;  rarely  slender 
orthorhombic  (pseudohexagonal)  crystals.  Cleavage  distinct,  two  directions 
at  70°  and  110°  (Oil);  brittle;  fracture  uneven. 


SEC.  8]  PHYSICAL  TABLES  49 

H. 

Color  white,  colorless,  grayish.     Streak  white.     Luster  vitreous.     Trans- 
lucent.    Taste  cool,  saline;  remains  dry  in  moist  air.     (See  p.  226.) 
On  rocks,  walls,  earth;  in  earth  of  some  caves;  in  soil. 

2      G.  1.0-2.0    SEPIOLITE  (Meerschaum),  H4Mg2Si3Oi0;  sometimes  Cu  and  Ni. 
2\        Struct. — Compact,  nodular,  earthy,  clay-like;  rarely  fibrous;  floats  when 
dry.     Cleavage  none;    brittle;    fracture  conchoidal,  uneven;    smooth  feel; 
adheres  to  tongue. 

Color  white,  grayish,  yellowish.     Streak  white.    Luster  dull.     Opaque. 
(See  p.  232,  254.) 

In  peridotites  and  serpentine  with  magnesite,  chlorite;    masses  in  strati- 
fied earthy  deposits. 

2      G.  1.7-1.8    EPSOMITE  (Epsom  Salt),  MgSO4-7H2O. 

2\  Struct. — Granular,  fibrous,  capillary,  incrusting,  earthy;  rarely  prismatic 
orthorhornbic  crystals.  Cleavage  distinct,  one  direction  (010);  brittle; 
fracture  conchoidal. 

Color  white,  colorless,  gray.     Streak  white.    Luster  vitreous,  dull.     Trans- 
parent to  translucent.     Taste  bitter,  salty.     (See  p.  224.) 
.    On  walls  and  floors  of  caves  and  mines  with  limestone,  gypsum,  serpen- 
tine, talc,  magnesite. 

2      G.  3.6-3.8     Hydrozincite  (Zinc  Bloom),  Zn3(OH)4CO3;  Zn  60.8%. 
2%        Struct.  Earthy,  compact,  fibrous,  incrusting,  stalactitic.     Cleavage  none; 
brittle;  fracture  uneven,  splintery. 

Color  white,  gray,  yellow.     Streak  white.     Luster  dull,  pearly.     Opaque. 
(See  p.  248.) 

With  calamine,  smithsonite,  other  secondary  zinc  minerals,  and  sphalerite. 

2      G.  5.2-5.3    Senarmontite,  Sb2O3;  Sb  83.3%. 

2|  Struct. — Isometric  crystals  (octahedrons,  Fig.  1);  granular,  incrusting; 
Cleavage  indistinct;  brittle;  fracture  uneven. 

Color  white,   colorless,  grayish.     Streak  white.     Luster  greasy,   pearly. 
Transparent  to  translucent.     (See  p.  212.) 
With  stibnite  and  other  antimony  minerals. 

2      G.  2.6-2.7     Pharmacolite  (Arsenic  Bloom),  HCaAsO4-2H2O. 
2|        Struct. — Fibrous,  acicular,  incrusting,  powdery;    small  prismatic  mono- 
clinic    crystals   rare.      Cleavage   distinct,    one   direction   lengthwise    (010); 
sectile,  thin  flakes  flexible;  fracture  uneven. 

Color  white,  grayish;   may  be  tinged  red  by  Co  or  green  by  Ni.     Streak 
white.     Luster  vitreous,  pearly.     Translucent  to  opaque.     (See  p.  228.) 
With  arsenopyrite  and  arsenical  ores  of  cobalt  and  silver. 

2\    G.  2.9-3.0    CRYOLITE,  Na3AlF6;   Na  32.8;   Al  12.8%. 

Struct. — Cleavable,  granular,  compact;   rarely  small  monoclinic  crystals, 
like  cubes  and  octahedrons.     Cleavage  none;  parting,  often  three  directions 
°,  90°,  92°  (001)  (110);   brittle;  fracture  uneven. 


50  DETERMINATIVE  MINERALOGY  [SEC.  8 

H. 

Color  white,  colorless,  brownish,  reddish.  Streak  white.  Luster  vitreous, 
greasy;  pearly  on  (001).  Transparent  to  translucent.  (See  p.  226.) 

Often  resembles  ice  or  paraffin.  In  veins  with  quartz,  siderite,  galena, 
sphalerite,  pyrite,  chalcopyrite,  fluorite. 


2  G.  2.0-2.2    DEWEYLITE  (Gymnite),  approx.  ILJVlg^SiO^s^HaO;  variable. 

3  Struct.  —  Amorphous,  like  gum  or  resin.     Cleavage  none;    brittle;    often 
much  cracked. 

Color  yellow,  white,  greenish,  reddish.     Streak  white.    Luster  greasy, 
resinous.     Translucent.     (See  pp.  232,  254.) 
In  serpentine  and  crystalline  limestone. 

%\    G.  1.0-1.1    AMBER  (Succinite,  Retinite),  Q»H«A. 

3  Struct.  —  Amorphous,  irregular  lumps,  grains.  Cleavage  none;  brittle; 
fracture  conchoidal;  sometimes  inclusions  of  insects,  vegetable  remains, 
liquids,  minerals. 

Color  yellow,  brownish  yellow,  brownish  red,  whitish.  Streak  white. 
Luster  greasy,  resinous.  Transparent  to  translucent.  Electrified  by  friction. 
(See  p.  212.) 

Fossil  resin  in  clays,  sands,  coal  beds,  sedimentary  rocks. 

2&     G.  2.3-2.4     GIBBSITE  (Hydrargillite),  A1(OH)3. 

3|  Struct.  —  Stalactitic,  botryoidal,  fibrous  or  scaly  aggregates;  tabular 
monoclinic  (pseudohexagonal)  crystals  rare.  Cleavage  one  direction  (001), 
seldom  observable;  tough. 

Color  white,  grayish,  greenish,  reddish.  Streak  white.  Luster  vitreous, 
dull,  pearly.  Translucent.  (See  p.  256.) 

Chief  constituent  of  some  bauxite  deposits;  with  corundum,  natrolite, 
limonite. 


G.  6.7-7.0    WULPENITE,  PbMoO4;  Pb  56.4%;  sometimes  Ca. 

Struct.  —  Thin  square  tabular  tetragonal  crystals,  sometimes  acute  pyram- 
idal; granular.  Cleavage  indistinct;  brittle;  fracture  conchoidal,  uneven. 

Color  yellow,  orange,  olive-green,  brown,  yellowish  gray,  whitish.  Streak 
white.  Luster  adamantine,  resinous.  Transparent  to  translucent.  (See 
p.  214.) 

In  oxidized  parts  of  lead  veins  with  galena,  pyromorphite,  vanadinite. 

G.  1.8-1.9    ALLOPHANE,  approx.  A]2Si05-5H20;  variable. 

Struct.  —  Amorphous,  incrusting,  stalactitic.  Cleavage  none;  brittle; 
fracture  conchoidal,  earthy. 

Color  sky-blue,  green,  yellow,  brown,  colorless.  Streak  white.  Luster 
vitreous,  waxy.  Translucent.  (See  p.  252.) 

Resembles  opal.  In  fissures  and  cavities  in  copper  and  iron  mines;  cavi- 
ties in  marls  and  limestones. 


SBC.  8]  PHYSICAL  TABLES  51 

H. 

3      G.  6.4-6.6    CERUSITE  (White  Lead  Ore),  PbCO3;  Pb  77.5%. 
3£        Struct. — Pseudohexagonal    orthorhombic    crystals,    clusters,    star-shaped 
groups;    granular,  fibrous,  compact.     Cleavage  indistinct;    brittle;    fracture 
conchoidal. 

Color  white,  gray,  colorless,  or  yellow,  brown,  etc.,  from  impurities.  Streak 
white.  Luster  adamantine,  greasy,  silky.  Transparent  to  translucent. 
(See  p.  214.) 

In  oxidized  parts  of  lead  ores  with  lead,  zinc,  iron,  and  copper  minerals. 

3  G.  2.5-2.6    SERPENTINE,  H4Mg3Si2O9;   commonly  Fe,  sometimes  Ni. 

4  Struct. — Massive,   compact;    fibrous  (chrysotile,  asbestos);   lamellar  (mar- 
molite);    columnar  (picrolite);    brittle;    fibers  flexible  and  tough;    fracture 
conchoidal,  splintery. 

Color  olive-green,  lalackish  green,  yellowish  green,  yellow;  rarely  white. 
Streak  white.  Luster  greasy,  waxy,  silky.  Translucent  to  opaque.  (See 
pp.  232,  254.) 

Common  alteration  product  of  olivine  rocks  (peridotites) ;  in  dolomitic 
limestone;  with  magnesite,  talc,  chromite,  magnetite,  corundum,  platinum, 
diamond.  Mixed  with  dolomite,  calcite,  or  magnesite  in  a  mottled  or  clouded 
green  marble  (verdantique,  or  ophicalcite) . 

3  G.  4.3-4.4    WITHERITE,  BaCO3;  BaO  77.7%. 

4  Struct. — Compact,  granular,  radial,    fibrous,    lamellar;    pseudohexagonal 
orthorhombic    crystals    resembling    quartz.     Cleavage    indistinct;     brittle; 
fracture  uneven. 

Color  white,  grayish,  yellowish.  Streak  white.  Luster  vitreous,  greasy. 
Transparent  to  translucent.  (See  p.  226.) 

In  veins  with  galena,  barite,  fluorite,  calcite. 

3J  G.  6.5-7.1  PYROMORPHITE  (Green  Lead  Ore),  Pb5Cl(PO4)3;  Pb  76.3%; 
4  P205  15.7%. 

Struct. — Small  prismatic  hexagonal  crystals,  often  rounded,  barrel- 
shaped,  sometimes  hollow;  incrusting,  reniform,  disseminated.  Cleavage 
none;  brittle;  fracture  conchoidal.  uneven. 

Color  green,  yellow,  brown,  white,  gray.  Streak  pale  yellow,  greenish 
yellow,  white.  Luster  resinous,  greasy,  adamantine.  Translucent  to  opaque. 
(See  p.  214.) 

In  oxidized  parts  of  lead  veins  with  galena,  cerusite,  mimetite,  barite, 
limonite. 

3£    G.  7.0-7.3     MIMETITE,  Pb5Cl(AsO4)3;  Pb  69.5%;  sometimes  Ca  and  P. 
4          Struct. — Prismatic,     tabular,     and    barrel-shaped    hexagonal     crystals; 
globular,  reniform,  incrusting.     Cleavage  indistinct;  brittle;  fracture  uneven. 
Color  yellow,  orange,  brown,  colorless.     Streak  white.    Luster  greasy, 
adamantine.     Translucent.     (See  p.  214.) 

In  oxidized  parts  of  lead  ores  with  galena  and  pyromorphite. 


52  DETERMINATIVE  MINERALOGY  [SBC.  8 

H. 

3J     G.  2.3-2.4    WAVELLITE,  (A1OH)3(PO4)2-5H2O;   P2O6  34.5%;   sometimes  F. 
4          Struct. — Radial    fibrous,  globular   with    crystalline    surface,    stalactitic; 
distinct  orthorhombic  crystals  rare.     Cleavage  three  directions  at  73°,  90°, 
and  107°  (101)  (010);   brittle;   fracture  uneven,  conchoidal. 

Color    green,    yellow,    white,    brown.     Streak    white.     Luster    vitreous, 
^pearly.     Translucent.     (See  pp.  252,  256.) 

In  clays  and  in  veins  and  joint  cracks  of  rocks;  with  oxides  of  iron  and 
manganese,  pyrite,  actinolite,  amblygonite. 

3|     G.  2.6-2.8    ALUNITE   (Alum  Stone),  KA13(OH)6(S04)2;    K2O  11.4%; 
4  A1203  37%. 

Struct. — Compact,  granular,  fibrous,  earthy;  hexagonal-rhombohedral 
crystals,  resembling  cubes,  rarely  tabular.  Cleavage  indistinct,  one  direc- 
tion (0001);  brittle;  fracture  conchoidal,  splintery,  earthy. 

Color  white,  grayish,  reddish.  Streak  white.  Luster  vitreous,  pearly. 
Transparent  to  opaque.  (See  pp.  248,  256.) 

Veins  and  replacements  in  feldspathic  rocks  with  quartz,  kaolin,  pyrite, 
opal. 

3|    G.  3.1-3.3    SCORODITE,  FeAs04-2H2O. 

4  Struct. — Pyramidal  orthorhombic  crystals,  sometimes  prismatic  or  tab- 
ular; botryoidal,  fibrous,  earthy,  amorphous.     Cleavage  imperfect,  two  direc- 
tions at  60°  and  120°  (120);  brittle;  fracture  conchoidal,  uneven. 

Color  pale  green,  bluish  green,  blackish  green,  blue,  brown.     Streak  white, 
grayish,  greenish.     Luster  vitreous,  greasy.     Translucent.     (See  p.  218.) 
With  arsenopyrite,  enargite,  limonite,  pyrite. 

4|    G.  3.1-3.2    APATITE  (Asparagus  Stone),  CaF(PO4)3;   P2O6  42.3%;   often 

5  some  Cl. 

Struct. — Prismatic  hexagonal  crystals,  sometimes  tabular;  granular, 
compact.  Cleavage  indistinct,  one  direction  crosswise  (0001);  brittle; 
fracture  conchoidal,  uneven. 

Color  green,  blue,  violet,  red,  brown,  white,  colorless.  Streak  white. 
Luster  vitreous,  greasy.  Transparent  to  opaque.  (See  pp.  228,  250.) 

In  crystalline  limestone  with  graphite,  fluorite,  pyrrhotite;  in  igneous 
rocks  (minute  crystals);  in  magnetite  ores;  with  fluorite  in  tin  and  tungsten 
ores;  amorphous  in  stratified  deposits  with  limestone  and  marl  (phosphorite, 
phosphate  rocks;  phosphatic  nodules). 

4|    G.  2.7-2.8    PECTOLITE,  HNaCa2(SiO3)3;  sometimes  Mn. 
5          Struct. — Fibrous,  radiating,  compact;  rarely  distinct  monoclinic  crystals. 
Cleavage  two  directions  at  85°  and  95°  (100)  (001);  brittle;  fracture  splintery. 
uneven. 

Color  white,  grayish,  reddish.  Streak  white.  Luster  vitreous,  silky. 
Translucent  to  opaque.  (See  p.  234.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  zeolites,  prehnite,  datolite,  native  copper,  calcite,  quartz,  epidote, 
pyrite,  chalcopyrite,  chlorite. 


SEC.  8]  PHYSICAL  TABLES  53 

H. 

5      G.  4.3-4.5    SMITHSONITE  (Dry  Bone;    Calamine,  in  England),  ZnC03; 

Zn52.1%. 

Struct. — Mammillary,  stalactitic,  incrusting;  cellular  (dry.  bone);  rarely 
small  hexagonal-rhombohedral  crystals.  Cleavage  distinct,  three  directions 
at  72°  and  108°  (lOll);  brittle;  fracture  uneven,  splintery. 

Color  white,  grayish,  colorless,  greenish,  blue,  pink,  brown.  Streak  white. 
Luster  vitreous,  adamantine,  pearly,  dull.  Transparent  to  opaque.  (See 
p.  248.) 

In  oxidized  zinc  ores,  usually  in  limestone  or  clay,  with  smithsonite, 
cerusite,  anglesite,  galena,  sphalerite,  calcite,  limonite. 

5      G.  2.9-3.0    DATOLITE,  Ca(BOH)Si04. 

5 §        Struct. — Complex    monoclinic  crystals;    granular,  compact;    botryoidal 
(botryolite) .     Cleavage  none;   brittle;   fracture  conchoidal,  uneven. 

Color  greenish,  colorless,  yellowish,  reddish,  grayish.  Streak  white. 
Luster  vitreous,  greasy,  dull.  Transparent  to  opaque.  (See  p.  230.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  metalliferous  veins; 
with  zeolites,  prehnite,  pectolite,  native  copper,  calcite,  quartz,  epidote, 
pyrite,  chalcopyrite,  chlorite. 

5      G.  2.2-2.3    ANALCITE  (Analdme,  a  zeolite),  NaAl(SiO3)2-H2O. 
5£        Struct. — Isometric  crystals  (trapezohedrons,  Fig.  3);   granular,  compact. 
Cleavage  none;  brittle;  fracture  uneven,  conchoidal. 
Color    white,    colorless,    grayish,    greenish,    yellowish,    reddish.     Streak 
white.     Luster  vitreous.     Transparent  to  opaque.     (See  p.  232.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  other  zeolites,  prehnite,  pectolite,  datolite,  native  copper,  calcite, 
quartz,  epidote,  pyrite,  chalcopyrite,  chlorite.  Sometimes  primary  constituent 
of  igneous  rocks. 

5      G.  2.3-2.4    THOMSONITE  (a  zeolite),  (Ca,Na2)2Al4(SiO4)4-5H2O. 
5$        Struct. — Radial  fibrous,  columnar,  spherical  concretions,  compact;  rarely 
distinct    prismatic    orthorhombic    crystals,    striated    lengthwise.     Cleavage 
two  directions  lengthwise  at  90°  (100)  (010);  brittle;  fracture  uneven. 

Color  white,  colorless,  reddish,  green,  brown.  Streak  white.  Luster 
vitreous,  silky,  pearly.  Transparent  to  opaque.  (See  p.  230.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite, 
quartz,  epidote,  pyrite,  chalcopyrite,  chlorite. 

5  G.  2.1-2.3    SODALITE  (a  feldspathoid),  Na4Al3Cl(SiO4)3. 

6  Struct. — Compact,     disseminated    grains,    nodular;     isometric    crystals 
(dodecahedrons)  rare.     Cleavage  indistinct,  six  directions  at  60°,  90°,  and 
120°  (110);   brittle;   fracture  conchoidal,  uneven. 

Color  blue,  gray,  white,  red,  green.  Streak  white.  Luster  vitreous, 
greasy.  Transparent  to  translucent.  (See  p.  230.) 

In  igneous  rocks  with  nephelite,  leucite,  cancrinite;   not  with  quartz. 


54  DETERMINATIVE  MINERALOGY  [SEC.  8 


5i    G.  2.4-2.5    LEUCITE  (Amphigene;  a  feldspathoid),  KAl(SiO,)2;  K2O  21.5%. 
6          Struct.  —  Isometric  crystals  (trapezohedrons,  Fig.  3),  rounded  disseminated 
grains.     Cleavage  indistinct,    brittle;   fracture  conchoidal. 

Color  white,  gray,  yellowish,  reddish,  colorless.  Streak  white.  Luster 
vitreous,  greasy.  Translucent  to  opaque.  (See  p.  254.) 

In  lavas  with  sanidine,  augite,  nephelite,  olivine;  not  with  quartz. 

5£    G.  3.0-3.3    JADE,  NaAl(SiO3)2  (Jadeite);  or  Ca(Mg,Fe)3(SiO3)4,  (Nephrite'). 
6|         Struct.  —  Very  tough  compact  varieties  of  the  amphiboles,  tremolite  and 
actinolite  (nephrite),  or  of  the  pyroxene,  jadeite;  fracture  splintery. 

Color  greenish,  grayish,  white,  Streak  white.  Luster  vitreous,  waxy, 
dull.  Translucent  to  opaque.  (See  pp.  36.  110.) 

Rolled  pebbles  in  clay;  ancient  or  oriental  utensils  and  art  objects.  Com- 
pare jade-like  compact  vesuvianite  (calif  'orni(e)  ,  p.  101. 

5|     G.  2.1-2.2    OPAL,  SiO2-nH2O;  H2O  2-16%,  chiefly  3-9%. 

6^  Struct.  —  Amorphous,  botryoidal,  reniform,  stalactitic,  earthy.  Cleavage 
none;  brittle;  fracture  conchoidal,  conspicuous  when  compact. 

Color  white,  yellow,  red,  brown,  green,  gray,  blue,  colorless;  sometimes  a 
rich  play  of  colors  (precious  opal).  Streak  white.  Luster  vitreous,  pearly, 
dull.  Transparent  to  opaque.  (See  pp.  256,  260,  264.) 

In  cavities  and  veins  in  igneous  and  sedimentary  rocks.  Precious  opal, 
play  of  colors;  fire  opal,  red,  transparent  or  translucent;  hyalite,  colorless, 
transparent,  like  melted  glass;  common  opal,  translucent  to  opaque,  greasy 
luster,  many  colors,  but  no  play  of  colors  —  including  milk  opal,  resin  opal, 
jasp-opal,  opal-agate;  geyserite,  siliceous  sinter,  porous,  hot  water  deposit; 
tripolite,  earthy,  from  leached  limestone;  diatomaceous  earth,  infusorial  earth, 
chalk-like,  clay-like,  composed  of  diatom  remains;  wood  opal,  replacing  fossil 
wood. 

6      G.  2.8-3.0    PREHNITE,  H2Ca2Al2(SiO4)3. 

6£  Struct.  —  Botryoidal,  stalactitic,  radial,  fibrous;  rounded  groups  of  tabular 
orthorhombic  crystals;  distinct  crystals  rare.  Cleavage  indistinct,  one  direc- 
tion (001);  brittle;  fracture.  uneven. 

Color  light  green,  oil-green,  gray,  white;  often  fading  on  exposure.  Streak 
white.  Luster  vitreous,  waxy.  Transparent  to  translucent.  (See  pp.  234, 
244.) 

With  zeolites,  datolite,  apophyllite,  pectolite,  native  copper,  calcite,  quartz, 
epidote,  chlorite  —  in  igneous  rocks,  chiefly  basic. 

6      G.  3.1-3.2    CHONDRODITE,   Mg6(F,OH)2(SiO4)2;  some  Fe  replaces  Mg. 
6|        Struct.  —  Rounded  disseminated  grains,  compact;    small  complex  mono- 
clinic    crystals    rare.     Cleavage    sometimes    distinct,    one    direction    (001); 
brittle;  fracture  conchoidal,  uneven. 

Color  brownish  red,  yellow,  white.  Streak  white.  Luster  vitreous, 
greasy.  Translucent  to  opaque.  (See  p.  252.) 

In  crystalline  limestone  with  spinel,  magnetite,  pyroxene,  vesuvianite, 
phlogopite,  corundum. 


SEC.  8]  PHYSICAL  TABLES  55 

H. 

6  G.  6.8-7.1     CASSITERITE( Tinstone},  Sn02;    Sn78.6%;    sometimes    Fe 

7  and  Ta. 

Struct. — Granular,  disseminated;  reniform  with  radiating  fibrous  struc- 
ture (wood  tin) ;  sand  and  pebbles  (stream  tin) ;  thick  prismatic  tetragonal 
crystals,  knee-shaped  twins  common  (Fig.  29).  Cleavage  indistinct;  brittle; 
fracture  uneven. 

Color  brown  to  black,  rarely  yellow,  red,  gray,  white.  Streak  white, 
grayish,  brownish.  Luster  adamantine,  greasy,  dull.  Transparent  to  opaque. 
(See  p.  262.) 

In  granite,  gneiss,  with  wolframite,  scheelite,  molybdenite,  tourmaline, 
fluorite,  topaz,  apatite,  lepidolite;  in  pegmatites;  in  sands  and  gravels. 

6£     G.  3.5-3.7    GROSSULARITE  (Essonite,  Hessonile,  Cinnamon  Stone;  a  garnet), 
71  Ca3Al2(SiO4)3;  often  some  Fe,  Mg,  Mn. 

Struct. — Isometric  crystals  (dodecahedrons,  trapezohedrons,  Figs.  3,  7); 
granular,  disseminated,  lamellar,  sand.  Cleavage  none;  parting,  seldom 
distinct,  six  directions  at  60°,  90°,  and  120°  (110);  brittle;  fracture  conchoidal, 
uneven. 

Color  white,  pink,  yellow,  brownish,  pale  green.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  (See  p.  244.) 

In  limestone  contacts  with  wollastonite,  vesuvianite,  diopside,  scapolite. 

7      G.  2.65         QUARTZ  (Rock  Crystal),  Si02. 

Struct. — Prismatic  hexagonal  crystals  striated  crosswise,  commonly 
terminated  by  double  rhombohedron  (like  hexagonal  pyramid);  granular, 
disseminated,  compact.  Cleavage  indistinct;  brittle;  fracture  conchoidal. 

Color  white,  colorless,  various  shades  (see  varieties,  below).  Streak 
white.  Luster  vitreous,  greasy.  Transparent  to  opaque.  (See  p.  262.) 

In  igneous  rocks,  gneiss,  schists,  sand,  sandstone,  quartzite;  common 
vein  mineral  with  many  metallic  ores. 

Varieties:  Rock  crystal,  colorless,  transparent;  amethyst,  purple,  blue 
violet  (color  destroyed  by  heat);  rose  quartz,  pink  to  rose-red  (fades  on  ex- 
posure); false  topaz,  citrine,  clear  yellow;  smoky  quartz,  cairngorm,  smoky 
yellow  to  black;  milky  quartz,  milk-white,  nearly  opaque;  cat's  eye,  opalescent 
from  inclosed  parallel  fibers  of  asbestos;  tiger  eye,  with  lustrous  yellow  to 
brown  parallel  fibers;  aventurine,  glistening  with  inclosed  scales  (mica,  hem- 
atite, etc.);  ferruginous  quartz,  yellow,  red,  or  brown  from  ferric  oxides. 

7      G.  2.6-2.64    CHALCEDONY  (Agate,  Flint,  Hornstone),  SiO2. 

Struct. — Compact,  botryoidal,  mammillary,  banded.  Cleavage  none; 
brittle  to  tough;  fracture  conchoidal. 

Color  white,  grayish,  brownish  to  black  (see  varieties  below).  Streak 
white.  Luster  waxy,  vitreous  to  nearly  dull.  Translucent  to  opaque.  (See 
p.  262.) 

Lining  or  filling  cavities  (agate,  etc.);  concretions  in  chalk  (flint)  or  lime- 
stone (chert,  hornslone). 

Varieties:  Carnelian,  sard,  clear  red  to  brownish  red;  chrysoprase,  apple- 
green;  plasma,  leek-green  to  bright  green;  heliotrope,  bloodstone,  bright  green 


56  DETERMINATIVE  MINERALOGY  [SEC.  8 

H. 

with  small  spots  of  red;  agate,  variegated,  generally  banded;  moss  agate,  with 
moss-like  or  tree-like  inclusions;  onyx,  banded  colors  in  flat  planes;  sardonyx, 
an  onyx  including  layers  of  sard,  or  carnelian;  siliceous  sinter,  cellular  deposi- 
tion from  siliceous  water  (see  also  opal) ;  flint,  whitish,  dull  gray,  smoky  brown 
to  black  (nodules  in  chalk) ;  chert,  hornstone,  like  flint,  but  more  brittle,  with 
splintery  fracture  (in  limestone);  basanite,  touchstone,  compact,  velvet-black; 
jasper,  impure  opaque,  red,  brown,  or  yellow  from  ferric  oxides. 

7      G.  2.3  Tridymite,  SiO2. 

Struct. — Minute  thin  tabular  hexagonal  crystals;  twins  common,  groups 
resembling  octahedron,  fan-shaped,  spherical  rosettes.  Cleavage  indistinct; 
brittle;  fracture  conchoidal. 

Color  white  or  colorless.  Luster  vitreous,  pearly.  Transparent.  (See 
p.  264.) 

In  cavities  in  acid  and  intermediate  volcanic  rocks;  with  sanidine,  horn- 
blende, augite,  hematite,  opal. 

7      G.  2.9-3.0    BORACITE,  Mg7Cl2Bi6O3o. 

Struct. — Isometric-tetrahedral  crystals  (tetrahedron,  cube),  small,  isolated; 
groups  rare;  granular.  Cleavage  indistinct;  brittle;  fracture  conchoidal, 
uneven. 

Color  white,  colorless,  grayish,  yellow,  green.  Streak  white.  Luster 
vitreous.  Transparent  to  opaque.  (See  pp.  228,  242.) 

Commonly  disseminated  glassy  crystals  with  gypsum,  anhydrite,  halite, 
carnallite. 

7      G.  3.0-3.2    TOURMALINE,  R9Al3(BOH)2(SiOs)4;    R=Mg,  Fe,  Ca,  Na, 
7|  K,  Li;  often  a  little  F. 

Struct. — Prismatic  hexagonal-rhombohedral  crystals,  hemimorphic,  curved 
triangular  in  cross-section,  striated  lengthwise  (Fig.  58) ;  radiating,  columnar, 
compact.  Cleavage  indistinct;  brittle  fracture  uneven,  conchoidal. 

Color  black  (schorl),  blue  (indicolite) ,  pink  to  red  (rubellite),  brown,  green; 
rarely  white  or  colorless  (achroite).  Streak  white.  Luster  vitreous,  resinous. 
Transparent  to  opaque.  '  (See  pp.  222,  242,  258.) 

In  pegmatite,  gneiss,  mica  schist,  slate,  gravels;  common  at  contacts;  with 
quartz,  feldspars,  beryl,  topaz,  cassiterite,  fluorite. 

7      G.  3.0  DANBURITE,  CaB2(SiO4)2. 

7  f        Struct. — Prismatic    orthorhombic    crystals,    like    topaz;     disseminated. 
Cleavage  indistinct;  brittle;  fracture  uneven,  conchoidal. 

Color  wine-yellow,  yellowish  white,  yellowish  brown.  Streak  white. 
Luster  vitreous,  greasy.  Transparent  to  translucent.  (See  p.  242.) 

With  calcite,  dolomite,  mica,  oligoclase,  microcline,  pyroxene,  tourmaline. 

7|    G.  4.5-1.8    ZIRCON,  ZrSiO4;  ZrO67.2%;   commonly  a  little  Fe. 

Struct. — Square  tetragonal  crystals  with  prism  and  pyramid;  irregular 
lumps,  disseminated  grains.  Cleavage  indistinct;  brittle;  fracture  uneven. 


SECS.  8,  9]  PHYSICAL  TABLES  57 

H. 

Color  gray,  brown,  yellow,  green;  red  transparent  (hyacinth};  colorless  or 
smoky  (jargon).  Streak  white.  Luster  adamantine,  vitreous.  Opaque  to 
transparent.  (See  p.  262.) 

Minute  grains  in  feldspathic  igneous  rocks;  rare  in  crystalline  limestone, 
gneiss,  schist;  with  magnetite,  apatite,  biotite,  wollastonite,  titanite;  in 
placers  with  gold,  corundum,  spinel,  garnet,  monazite. 

7|     G.  2.6-2.8    BERYL,  Gl3Al2(SiO3)6;  a  little  H,  sometimes  Na,  Li,  Cs. 

8  Struct. — Prismatic  hexagonal  crystals,  often  large,  rough,  and  striated 
lengthwise   (Fig.  49);    columnar,   granular,   compact.     Cleavage  indistinct; 
brittle;  fracture  uneven,  conchoidal. 

Color  bright  green  (emerald),  blue,  greenish  blue  (aquamarine),  yellow 
(golden  beryl),  pink  (rose  beryl,  morganite),  colorless.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  (See  pp.  244,  260.) 

In  pegmatite;  less  common  in  granite,  mica  schist,  slate;  in  bituminous 
limestone.  With  topaz,  tourmaline,  garnet,  chrysoberyl,  rutile. 

9  G.  3.9-4.1     CORUNDUM  (Adamantine  Spar),  A1203. 

Struct. — Rough  hexagonal-rhombohedral  crystals,  prismatic,  pyramidal, 
tabular,  tapering  (barrel-shaped),  often  striated;  lamellar,  granular,  compact. 
Cleavage  none;  often  conspicuous  parting,  three  directions  at  86°  and  94° 
(lOll);  sometimes  transverse  parting  (0001);  brittle,  tough  when  compact; 
fracture  uneven,  conchoidal. 

Color  white,  gray,  brown  to  black;  deep  red  (ruby);  blue  (sapphire); 
black  from  admixture  of  magnetite,  hematite,  or  spinel  (emery).  Streak 
white.  Luster  vitreous,  adamantine.  Transparent  to  opaque.  (See  p.  260.) 

In  peridotite,  gneiss,  schist,  syenite,  crystalline  limestone;  with  olivine, 
chlorite,  serpentine,  magnetite,  spinel,  vermiculite;  cyanite,  diaspore,  mus- 
covite. 

SECTION  9 

Streak  chalk- white,  colorless,  or  pale  colored;  mineral  dark  gray 
to  black;   distinct  cleavage  one  direction  only. 

1  G.  2.8-2.9    PYROPHYLLITE  (Pencil  Stone),  H2Al2(SiO3)2. 

2  Struct.  —  Foliated,  granular,  fibrous,  radial,  compact;    indistinct  ortho- 
rhombic  crystals  rare.    Cleavage  perfect,  one  direction  (001) ;  fracture  uneven, 
splintery;  thin  flakes  flexible,  not  elastic;  feel  greasy. 

Color  white,  apple-green,  gray,  yellow.  Streak  white.  Luster  pearly  to 
dull.  Translucent  to  opaque.  (See  p.  256.) 

In  schistose  rocks  with  cyanite,  topaz,  graphite,  lazulite. 

1      G.'2.5-2.8    TALC  (Steatite,  Soapstone,  Potstone),  H2Mg3(Si03)4. 

2|  Struct. — Foliated,  granular;  fibrous  (agolite);  compact  (soft,  French  chalk; 
waxy,  rensselaerit e) ;  indistinct  tabular  monoclinic  crystals  rare.  Cleavage 
perfect,  one  direction  (001);  thin  flakes  flexible,  not  elastic;  sectile;  fracture 
uneven;  greasy  feel.  Hardness  sometime  3-4. 


58  DETERMINATIVE  MINERALOGY  [SEC.  9 

H. 

Color  apple-green,  gray,  white.  Streak  white.  Luster  pearly,  greasy. 
Transparent  to  opaque.  (See  pp.  236,  246,  256.) 

In  crystalline  schists;  with  serpentine,  dolomite,  magnesite,  chlorite, 
actinolite. 

1|     G.  2.6-2.7    VIVIANITE  (Blue  Iron  Earth),  Fe3(PO4)2-8H2O;  P2O5  28.3%. 
2          Struct. — Radial  fibrous,  earthy;    prismatic  and  tabular  monoclinic  crys- 
tals.    Cleavage  distinct,  one  direction  (010);    sectile;    thin  flakes  flexible; 
fracture  splintery,  earthy. 

Color  blue,  green,  greenish  black;  colorless  when  fresh.  Streak  white, 
greenish  blue.  Luster  pearly  on  cleavage;  vitreous,  dull.  Transparent  to 
opaque.  (See  p.  218.) 

In  clay,  marl,  peat;  in  cavities  of  fossils;  with  limonite;  in  veins  with 
pyrrhotite,  pyrite,  gold. 

1§    G.  2.3-2.4    GYPSUM  (Selenite,  Alabaster,  Satin  Spar),  CaSO4-2H2O. 
2          Struct. — Granular,  foliated,  fibrous;    earthy   (gypsite);    diamond-shaped 
monoclinic  crystals  with  beveled  edges  (Figs.  38,  39).     Cleavage  perfect,  one 
direction  (010),  two  others  less  conspicuous  (111)  (100)  at  90°,  66°,  and  114°; 
brittle,  thin  flakes  flexible;  fracture  conchoidal,  splintery. 

Color  white,  colorless,  gray,  yellow,  red.  Streak  white.  Luster  vitreous; 
pearly  on  (010);  silky.  Transparent  to  opaque.  (See  pp.  224,  226.) 

Beds  and  masses  with  limestone,  shale,  clay,  rock  salt;  near  volcanic 
vents;  with  anhydrite,  celestite,  sulphur,  calcite,  aragonite. 

2      G.  1.7  BORAX  (Tinkal),  Na2B4O7-10H2O;   B2O3  36.6%. 

2J        Struct. — Compact,  earthy,  incrusting;    short  columnar  monoclinic  crys- 
tals.    Cleavage  distinct,  one  direction  (100);   brittle;   fracture  conchoidal. 

Color  white,  colorless,  grayish,  bluish,  greenish.  Streak  white.  Luster 
vitreous,  greasy.  Translucent  to  opaque.  Sweetish  alkaline  taste.  (See 
pp.  226,  228.) 

In  mud  of  alkaline  lakes  and  marshes  with  halite,  gypsum,  colemanrte. 

2  G.  2.7-3.0    MUSCOVITE  (Common  or  White  Mica,  Potash  Mica,  Isinglass) 

3  HsKAl3(SiO4)i;  often  a  little  Na,  Ca,  Mg,  Fe,  and  F. 
Struct. — Foliated,  flaky;  fine  scaly  to  fibrous  (sericite,  damourite);   dense 

(pinite);  rarely  distinct  monoclinic  (pseudohexagonal)  crystals.  Cleavage 
perfect,  one  direction  (001);  thin  flakes  tough,  very  elastic. 

Color  white,  gray,  yellowish,  greenish,  brownish.  Streak  white.  Luster 
vitreous,  pearly.  Transparent  to  translucent.  (See  p.  236.) 

In  pegmatite,  granite,  gneiss,  schists,  contacts;  with  feldspars,  quartz, 
tourmaline,  beryl,  garnet. 

2  G.  2.8-3.1    BIOTITE     (Black     Mica,     Ferromagnesian     Mica), 

3  (H;K)2(Mg,Fe)2Al2(SiO4)3;  a  little  F;  often  Ti. 

Struct. — Plates,  scales;  pseudohexagonal  monoclinic  crystals  rare.  Cleav- 
age conspicuous,  one  direction  (001);  thin  flakes  tough,  very  elastic,  becoming 
more  brittle  with  alteration. 


SEC.  9]  PHYSICAL  TABLES  59 

H. 

Color  black,  brownish  black,  greenish  black,  dark  green.  Streak  white. 
Luster  pearly,  submetallic.  Transparent  to  opaque.  (See  pp.  204,  220,  236.) 

Common  in  granite,  syenite,  gneiss,  mica  schist;  less  common  in  basic 
igneous  rocks  and  contacts. 

2  G.  2.8-2.9    PHLOGOPITE  (Amber  Mica,  Bronze  Mica,  Magnesia  Mica), 

3  H2KMg3Al(SiO4)3;  some  F  and  Fe. 

Struct. — Plates,  scales;  prismatic  or  tabular  monoclinic  crystals  with 
hexagonal  or  orthorhombic  outline,  commonly  rough.  Cleavage  conspicuous, 
one  direction  (001);  thin  flakes  tough,  very  elastic. 

Color  yellowish  brown,  brownish  red,  gray  to  green;  rarely  colorless. 
Streak  white.  Luster  pearly,  submetallic.  Translucent  to  transparent. 
(See  pp.  204,  236.) 

Contacts  in  crystalline  limestone;  in  serpentine;  with  pyroxene,  amphibole, 
serpentine,  graphite,  apatite,  corundum. 

2  G.  2.8-2.9     Paragonite  (Soda  Mica),  H2NaAl3(SiO4)3. 

3  Fine  scaly  masses,  compact;  strong  pearly  luster.     Otherwise  like  musco- 
vite  above.     In  schists  with  cyanite,  staurolite,  tourmaline,  garnet,  actinolite. 
(See  p.  236.) 

3  G.  2.5-2.8    TALC  (Steatite,  Soapstene,  Potstone),  H2Mg3(Si03)4. 

4  Struct. — Foliated,  granular;  fibrous  (agolite);  compact  (soft,  French  chalk; 
waxy,  rensselaerite) ;    indistinct  tabular  monoclinic  crystals  rare.     Cleavage 
perfect,  one  direction  (001) ;  thin  flakes  flexible,  not  elastic;  sectile;  fracture 
uneven;   greasy  feel.     Hardness  commonly  1-2|. 

Color  apple-green,  gray,  white.  Streak  white.  Luster  pearly,  greasy. 
Transparent  to  opaque.  (See  pp.  236,  246,  256.) 

In  crystalline  schists;  with  serpentine,  dolomite,  magnesite,  chlorite, 
actinolite. 

3|     G.  3.0-3.1     MAKGARITE  (Brittle  Mica),  H2CaAl4Si2Oi2;  some  Fe,  Na,  K. 
4|        Struct. — Micaceous,  scaly,  granular;   six-sided  scales,  plates  (monoclinic). 
Cleavage  perfect,  one  direction  (001);  flakes  rather  brittle,  not  elastic. 

Color  pink,  grayish,  white,  yellowish.  Streak  white.  Luster  pearly 
on  cleavage;  vitreous.  Translucent.  (See  pp.  236,  256.) 

Coating  or  associated  with  corundum;  also  chlorite,  spinel,  emery,  diaspore. 

5  G.  3.3-3.5    HYPERSTHENE  (a  pyroxene),  (Fe,Mg)SiO3;  sometimes  Al. 

6  Struct. — Foliated,     cleavable,     granular;     orthorhombic    crystals    rare. 
Cleavage  perfect,  one  direction  (010),  less  distinct  in  two  directions  (110),  at 
46°,  88°,  92°,  134°;  brittle;  fracture  uneven. 

Color  grayish,  greenish,  and  brownish  black  to  bronze.  Streak  brownish 
gray,  grayish  white.  Luster  metalloidal,  bronzy,  pearly.  Opaque  to  trans- 
lucent. (See  pp.  222,  258.) 

In  basic  igneous  rocks  with  plagioclase  feldspars,  olivine,  amphibole, 
pyroxene,  magnetite,  titanite;  seldom  with  quartz. 


60  DETERMINATIVE  MINERALOGY  [SEC.  9 

H. 

6      G.  3.2-3.4    ZOISITE,  Ca2Al3(OH)(SiO4)3;  oftensomeFe. 
6|        Struct. — Columnar,   bladed,   fibrous,   compact;    prismatic  orthorhombic 
crystals   striated  lengthwise,  without  terminations.     Cleavage   conspicuous, 
one  direction  lengthwise  (010) ;  brittle;  fracture  uneven. 

Color  gray,  yellowish  brown,  greenish;    also  red  (thulile).     Streak  white. 
Luster  vitreous;  pearly  on  cleavage.     Transparent  to  opaque.     (See  p.  246.) 
In   crystalline   schists   with   hornblende,    vesuvianite,    cyanite,    epidote, 
garnet,  feldspars,  quartz. 

6  G.  3.2-3.5    EPIDOTE  (Pistacite),  Ca«(Al,Fe),(OH)(SiO4)i. 

7  Struct. — Long  monoclinic  crystals  striated  lengthwise,  commonly  termi- 
nated by  two  sloping  faces;   columnar,  divergent  acicular,  granular.     Cleav- 
age distinct,  one  direction  lengthwise  (001);  brittle;  fracture  uneven. 

Color  yellowish  green  to  brown  and  black,  gray,  yellow,  red.  Streak 
white  to  grayish.  Luster  vitreous.  Transparent  to  opaque.  (See  pp.  222, 
246.) 

In  gneiss,  schist,  crystalline  limestone,  greenstone,  with  garnet,  magnetite, 
chlorite,  native  copper,  zeolites. 

6  G.  3.3-3.5    DIASPORE,  A1O- OH;  Al  45%;  sometimes  Fe. 

7  Struct. — Scaly,    bladed,    fibrous;     columnar   and    tabular   orthorhombic 
crystals  rare.     Cleavage  distinct,  one  direction  (010);   brittle;   fracture  con- 
choidal. 

Color  white,  grayish,  greenish,  hair-brown,  yellow,  colorless.  Streak 
white.  Luster  vitreous;  pearly  on  cleavage.  Transparent  to  opaque.  (See 
p.  260.) 

With  corundum,  emery,  dolomite,  margarite,  chlorite,  magnetite. 

6  G.  3.3-3.4    AXINITE,  HCasAl2B(SiO4)4;  sometimes  Mn,  Fe,  Mg. 

7  Struct. — Tabular   wedge-shaped   triclinic    crystals    (Fig.    45);     lamellar, 
granular.     Cleavage  distinct,  one  direction  (010) ;  brittle;  fracture  conchoidal. 

Color  clove-brown,  yellow,  greenish,  grayish  blue,  gray.     Streak  white. 
Luster  vitreous.     Transparent  to  translucent.     (See  p.  242.) 
In  veins  with  quartz,  feldspars,  hornblende,  chlorite. 

6  G.  3.5-3.6    Chloriioid  (Ottrelite) ,  H2FeAl2SiO7;  some  Mg,  sometimes  Mn. 

7  Struct. — Foliated,  scaly,  rosette  groups;   rarely  tabular  triclinic  crystals, 
hexagonal  in  outline.     Cleavage  perfect,  one  direction  (001);    thin  flakes 
brittle.     (Oltrelile,  oblong  scales). 

Color  dark  gray,  greenish  gray,  greenish  black.  Streak  white,  grayish, 
pale  green.  Luster  pearly,  vitreous.  Translucent  to  opaque.  (See  p.  222, 
258,  260.) 

In  hornfels,  slate,  schist;  with  chlorite,  hornblende,  garnet,  corundum. 

7      G.  2.6-2.7     CORDIERITE    (Mite,    Dichroite,    Water  Sapphire), 

7§  (Mg,Fe)4Al8(OH)2(Si207)5. 

Struct. — Short  six-  or  twelve-sided  orthorhombic  (pseudohexagonal) 
crystals;  granular,  compact,  disseminated.  Cleavage  one  direction  length- 
wise (010);  parting  sometimes  conspicuous  crosswise  (001);  brittle;  fracture 
uneven,  conchoidal. 


SECS.  9,  10]  PHYSICAL  TABLES  61 

H. 

Color  light  to  dark  smoky  blue,  gray,  violet,  yellow.  Resembles  blue 
quartz;  often  altering  to  dull  green  chlorite;  transparent  varieties  show 
marked  differences  in  color  in  different  directions.  Streak  white.  Luster 
vitreous,  dull.  Transparent  to  translucent.  (See  p.  244,  260.) 

In  schists,  gneiss,  sometimes  in  granite;  with  quartz,  feldspars,  hornblende, 
tourmaline,  andalusite,  sillimanite,  garnet. 

SECTION  10 

Streak  chalk- white,  colorless,  or  pale  colored;  mineral  dark  gray 
to  black;  distinct  cleavage  two  directions. 

3k    G.3.7  STRONTIANITE  (Strontian  Spar),  SrCO3;  SrO  70.1%;  some- 

4  times  Ca. 

Struct. — Chisel-  or  spear-shaped  orthorhombic  crystals,  pseudohexagonal 
prisms;  columnar,  acicular,  fibrous,  divergent;  granular,  compact;  Cleavage 
distinct,  two  directions  at  63°  and  117°  (110);  brittle;  fracture  uneven. 

Color  white,  colorless,  grayish,  greenish,  yellowish.  Streak  white.  Luster 
vitreous,  greasy.  Transparent  to  translucent.  (See  p.  246.) 

In  ore  deposits  with  galena,  barite,  calcite,  celestite,  fluorite,  pyrite; 
veins  in  limestone,  chalk,  marl. 

4  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  Al2SiO6,  or  (AlO)2Si03. 

5  Struct. — Long  tabular  or  bladed  triclinic  crystals  without  terminations; 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  length- 
wise at  74°  and  106°  (100)  (010);  transverse  parting  (001)  common;  brittle; 
fracture  splintery. 

Color  blue,  white,  gray,  green,  nearly  black;  often  streaked.  Streak 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  p.  256,  260.) 

Hardness  lengthwise  4-5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum. 

5      G.  3.4-3.6    TITANITE  (Spheric),  CaSiTiO6;   commonly  a  little  Fe. 

65  Struct. — Tabular  or  wedge-shaped  monoclinic  crystals;  lamellar,  com- 
pact. Cleavage  distinct,  two  directions  at  66i°  and  113J°  (110);  parting 
often  distinct  four  directions  at  54°  and  126°  (221);  brittle;  fracture  con- 
choidal. 

Color  brown  to  black,  yellow,  gray,  green;  rarely  rose-red.  Streak  white. 
Luster  vitreous,  resinous,  adamantine.  Transparent  to  opaque.  (See  p. 
234,  246.) 

Accessory  in  many  igneous  rocks;  in  gneiss,  chlorite  schist,  crystalline 
limestone;  with  chlorite,  iron  oxides,  pyroxene,  amphibole,  zircon,  apatite, 
feldspars,  quartz,  rutile. 

5  G.  2.9-3.4    HORNBLENDE  (an  amphibole),  Silicate  of  Ca,  Mg,  Fe,  Al,  etc. 

6  Struct. — Granular,    columnar,   fibrous,   radiated;    long  prismatic  mono- 
clinic  crystals,   often  rhombohedron-like  terminations;    prism  angle   124°; 
some  prisms  short,  six-sided.      Cleavage  perfect,  two   directions  lengthwise 
at  56°  and  124°  (110);  brittle;  fracture  uneven,  splintery. 


62  DETERMINATIVE  MINERALOGY  [SBC.  10 

H. 

Color  green,  black,  brown,  gray.  Streak  brown,  green,  yellow,  gray, 
white.  Luster  submetallic,  vitreous,  pearly,  silky.  Translucent  to  opaque. 
(See  pp.  222,  238.) 

Common  in  igneous  and  metamorphic  rocks  with  feldspars,  pyroxenes, 
chlorite,  quartz,  calcite. 

5  G.  2.9-3.1     TREMOLITE  (Grammatite,  an  amphibole),  CaMg3(Si03)4. 

6  Struct. — Bladed,  columnar,  fibrous,  compact;   bladed  monoclinic  crystals 
without  terminations;  prism  angle  124°.   Cleavage  conspicuous,  two  directions 
lengthwise,  56°  and  124°  (110);  brittle;  small  fibers  flexible;  fracture  uneven. 
Nephrite  or  jade,  in  part  tremolite,  is  dense,  compact,  tough. 

Color  white  to  dark  gray,  yellowish,  colorless.  Streak  white.  Luster 
vitreous,  silky,  pearly.  Transparent  to  opaque.  (See  p.  238.) 

In  limestone,  dolomite,  schist;  common  at  contracts;  with  pyroxene, 
garnet,  vesuvianite,  epidote. 

5  G.  3.0-3.2     Anthophyllite   (an  amphibole),    (Mg,Fe)SiO3;    sometimes  Al 

6  (Gedrite). 

Struct. — Lamellar,  columnar,  fibrous;  prismatic  orthorhombic  crystals 
rare.  Cleavage  two  directions  lengthwise  at  545°  and  125J°  (110);  brittle; 
fracture  splintery;  fine  fibers  flexible  (asbestos). 

Color  gray,  clove-brown,  greenish  to  emerald.  Streak  white.  Luster 
vitreous,  pearly,  silky,  sometimes  metalloidal.  Translucent  to  opaque. 
(See  pp.  222,  238,  258.) 

In  schists  with  talc,  hornblende,  chlorite,  mica. 

5  G.  3.2-3.6    PYROXENE,     Ca(Mg,Fe)(SiO3)2,     ranging    from     Diopside, 

6  CaMg(SiO3)2,  to   Hedenbergite,    CaFe(SiO3)2;    often   some 
Al,  Mn,  and  Na. 

AUGITE  (a  pyroxene),  like  common  pyroxene  above,  with 
A12O3  up  to  15%  or  20%;  sometimes  Na  and  K. 

Struct. — Granular,  columnar,  rarely  fibrous;  lamellar  (diallage);  thick 
monoclinic  prisms  four  or  eight-sided  (Figs.  40,  41).  Cleavage  two  directions 
lengthwise  at  87°  and  93°  (110),  sometimes  distinct;  often  prominent  parting 
crosswise  (001);  diallage  has  fine  lamellar  parting  one  direction  lengthwise 
(100);  brittle;  fracture  uneven. 

Color  bright  to  dark  green,  grayish  green,  black,  brown.  Streak  greenish, 
brownish,  grayish  to  white.  Luster  vitreous,  submetallic,  dull.  Transparent 
to  opaque.  (See  pp.  220,  222,  240.) 

Common  in  basic  igneous  rocks;  in  crystalline  limestones  with  garnet, 
chlorite,  amphibole,  wollastonite,  magnetite,  pyrite. 

5  G.  3.2-3.6    DIOPSIDE  (Malacolite,  a  pyroxene),  CaMg(SiO3)2;  some  Fe. 

6  Struct. — Prismatic  monoclinic  (pseudo tetragonal)  crystals,  stout,  termi- 
nated (Figs.  40,  41);   lamellar,  granular,  compact.     Cleavage  two  directions 
lengthwise  at  87°  and  93°  (110)  sometimes  distinct;  often  conspicuous  trans- 
verse parting  (001);  brittle;  fracture  uneven. 


SEC.  10]  PHYSICAL  TABLES  63 

H. 

Color  white,  colorless,  grayish,  green  to  black.  Streak  white,  grayish, 
greenish.  Luster  vitreous,  dull.  Transparent  to  opaque.  (See  p.  240.) 

In  basic  igneous  rocks;  in  crystalline  limestones  with  wernerite,  vesuvian- 
ite,  garnet. 

5|     G.  4.0-4.1     Tephroile,  Mn2SiO4;  commonly  also  Mg  and  a  little  Fe. 
6          Struct. — Cleavable,    granular,    compact;     orthorhombic    crystals    rare. 
Cleavage  distinct,  two  directions  at  90°;  brittle;  fracture  conchoidal,  uneven. 
Color  ash-gray,   flesh-red,  brown.     Streak  pale  gray.     Luster  vitreous, 
greasy.     Translucent  to  opaque.     (See  p.  230.) 

In  crystalline  limestone  with  zincite,  willemite,  franklmite,  rhodonite 
(Franklin,  N.  J.);  with  other  manganese  minerals. 

6  G.  2.5-2.6— ORTHOCLASE  (Potash  Feldspar),  KAlSisOgj  K20 16.9%; 
6£  often  Na. 

Struct. — Cleavable,  granular,  disseminated  grains;  prismatic  and  tabular 
monoclinic  crystals  and  twins  (Figs.  42  to  44).  Cleavage  distinct,  two  direc- 
tions  at  90°  (010)  (001);  brittle;  fracture  conchoidal,  uneven. 

Color  white,  red,  gray,  green,  colorless.  Streak  white.  Luster  vitreous; 
often  pearly  on  cleavage.  Transparent  to  opaque.  (See  p.  238.) 

In  many  igneous  and  metamorphic  rocks;  in  veins  and  contacts;  with 
quartz,  other  feldspars,  mica,  hornblende,  pyroxene;  in  pegmatite  with  beryl, 
topaz,  tourmaline.  For  varieties  see  p.  37. 

6  G.  2.6-2.8  PLAGIOCLASE  (Soda-lime  and  Lime-soda  Feldspars),  ranging 
6J  from  NaAlSi3O8  (ab)  to  CaAl2Si2O8  (an) ;  generally  some  K. 

Comp.  Sp.  Gr.  Comp.  Sp.  Gr. 

Albite,         ab-abeani  2.62-2.64     Labradorite,  abiani-abian3,   2.70-2.72 

Oligoclase,  abeani-abiani,    2.65-2.67     Bytownite,      ab,an3-ab1an6,    2.73-2.75 
Andesine,    abjani-abiani,   2.68-2.69    Anorthite,       abianr-an,          2.75-2.76 

Struct. — Lamellar,  granular,  disseminated;  small  tri  clinic  crystals  (Fig.  46). 
Cleavage  distinct,  two  directions  at  86°-86i°  and  94°-93J°  (001)  (010);  often 
striations  on  one  cleavage;  cleavage  often  curved;  brittle;  fracture  uneven. 

Color  white,  colorless,  gray,  green,  bluish,  reddish;  sometimes  play  of 
colors — blue,  green,  yellow,  red.  Streak  white.  Luster  vitreous;  often 
pearly  on  cleavage.  Transparent  to  opaque,  sometimes  opalescent  (moon- 
stone), or  with  bright  reddish  or  yellowish  reflections  from  included  scales 
(av enturine  feldspar,  or  sunstone).  (See  p.  238.) 

In  igneous  rocks,  gneisses,  schists;  with  other  feldspars,  quartz,  mica, 
chlorite,  zeolites;  sometimes  in  veins. 

6      G.  3.5-3.6     Aegirite  (Aegirine,  Acmite,  a  pyroxene),  NaFe'"(SiO3)2. 
6J        Struct. — Long    prismatic    monoclinic    crystals    with    terminations    blunt 
(aegirite)  or  sharp  (acmile);   acicular,  fibrous.     Cleavage  distinct,  two  direc- 
tions at  87°  and  93°  (110);  brittle;  fracture  uneven. 

Color  greenish  black  to  reddish  and  brownish  black;  acmile  often  green 
interior,  brown  exterior.  Streak  pale  yellowish  gray.  Luster  vitreous, 
resinous.  Translucent  to  opaque.  (See  pp.  222,  240.) 

In  igneous  rocks  rich  in  soda  and  iron — aegirite  granite,  nephelite  syenite, 
phonolite,  pegmatite. 


64  DETERMINATIVE  MINERALOGY  [Sees.  10,  11 

H. 

6      G.  3.0-3.1    Glaucophane  (an  amphibole),  Na(Mg,Fe,Ca)Al(SiO3)3. 

65  Struct. — Columnar,    fibrous,    granular;     prismatic    monoclinic    crystals, 
commonly  indistinct.     Cleavage   distinct,  two   directions  lengthwise  at  58° 
and  122°  (110);  brittle,  small  fibers  flexible;  fracture  uneven,  conchoidal. 

Color  lavender  blue,  azure  blue,  bluish  to  grayish  black.  Streak  white. 
Luster  vitreous,  pearly,  silky.  Translucent  to  opaque.  (See  p.  238.) 

In  schists  and  gneisses  with  mica,  garnet,  epidote,  zoisite,  amphiboles, 
pyroxenes. 

6  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  Al2SiO6,  or  (AlO)2SiO3. 

7  Struct. — Long  tabular  or  bladed  triclinic  crystals  without  termination; 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  length- 
wise at  74°  and  106°  (100)  (010);   transverse  parting  (001)  common;  brittle; 
fracture  splintery. 

Color  blue,  white,  gray,  green,  nearly  black;  often  streaked.  Streak 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  pp.  256,  260.) 

Hardness  lengthwise  4-5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum. 

6  G.  3.1-3.2    SPODUMENE  (a  pyroxene),  LiAl(SiO3)2;  Li2O  8.4%;  some  Na. 

7  Struct. — Cleavable,    columnar,    compact;    rough   prismatic   or   flattened 
monoclinic  crystals,  striated  lengthwise.     Cleavage  conspicuous,  two  direc- 
tions lengthwise  at  87°  and  93°  (110);    parting  sometimes  prominent  one 
direction  (100),  bisecting  larger  cleavage  angle;    brittle;    fracture  uneven, 
splintery. 

Color  white,  gray,  yellowish;  emerald-green  (hiddenite);  pink  to  purple 
(kunzile).  Streak  white.  Luster  vitreous,  pearly.  Transparent  to  opaque. 
(See  pp.  240,  242.) 

In  pegmatites  with  tourmaline,  lepidolite,  beryl,  amblygonite,  cassiterite. 

6|     G.  3.1-3.2    ANDALUSITE  (Chiastolite,  Made),  Al2SiO5,  or  Al(AlO)SiO4. 
7 1        Struct. — Columnar,  granular,  disseminated;   rough  orthorhombic  prisms, 
nearly  square.      Cleavage    distinct,  two  directions  at  89°  and  91°   (110); 
brittle;  fracture  uneven. 

Color  white,  pink,  reddish  brown,  olive-green;  sometimes  black  and  white 
cross  or  checkered  pattern  on  cross-fracture  (chiastolite,  or  made).  Streak 
white.  Luster  vitreous,  dull.  Translucent  to  opaque.  (See  p.  260.) 

In  slate,  schists,  and  gneiss;  with  sillimanite,  garnet,  biotite,  tourmaline, 
cordierite. 

SECTION  11 

Streak  chalk- white,  colorless,  or  pale  colored;  mineral  dark  gray 
to  black;  distinct  cleavage  three  or  more  directions. 

1|    G.  2.3-2.4    GYPSUM  (Selenite,  Alabaster,  Satin  Spar),  CaSO4-2H2O. 

2  Struct. — Granular,  foliated,  fibrous;  earthy  (gypsite);  diamond-shaped 
monoclinic  crystals  with  beveled  edges  (Figs.  38,  39).  Cleavage  perfect,  one 
direction  (010),  two  others  less  conspicuous  (111)  (100)  at  90°,  66°,  and  114°; 
brittle,  thin  flakes  flexible;  fracture  conchoidal,  splintery. 


SEC.  11]  PHYSICAL  TABLES  65 

H. 

Color  white,  colorless,  gray,  yellow,  red.  Streak  white.  Luster  vitreous; 
pearly  on  (010);  silky.  Transparent  to  opaque.  (See  pp.  224,  226.) 

Beds  and  masses  with  limestone,  shale,  clay,  rock  salt;  near  volcanic 
vents;  with  anhydrite,  celestite,  sulphur,  calcite,  aragonite. 

2      G.  2.1-2.6    HALITE  (Common  Salt,  Rock  Salt),  NaCl;   Na  60.6%;   often 
2|  Ca  and  Mg. 

Struct. — Granular,  cleavable,  compact;  isometric  crystals  (cubes,  Fig.  5). 
Cleavage  distinct,  three  directions  at  90°  (100);  brittle;  fracture  conchoidal. 
Color  white,  colorless,  grayish,  reddish,  bluish.     Streak  white.    Luster 
vitreous.     Transparent  to  translucent.     Taste  salty.     (See  p.  224.) 

Beds  in  sedimentary  strata  with  gypsum,  anhydrite,  sylvite,  calcite,  clay, 
sand;  in  dry  lakes;  in  brines. 

2  G.  1.9-2.0    SYLVITE,  KC1;  K  52.4%;  sometimes  Na. 

2?  Struct. — Granular,  compact;  isometric  crystals  (cubes,  Fig.  5).  Cleavage 
distinct,  three  directions  at  90°  (100);  brittle;  fracture  conchoidal. 

Color  white,  colorless,  grayish,  bluish,  reddish.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  Taste  salty,  bitter.  Becomes  damp 
in  moist  air.  (See  p.  224.) 

In  salt  deposits;  with  halite,  kainite,  carnallite. 

3  G.  2.7          CALCITE  (Cole  Spar),  CaCO3;  often  Mg,  Fe,  Mn,  sometimes  Pb. 

Struct.  —  Hexagonal-rhombohedral  crystals,  prismatic,  scalenohedral, 
rhombohedral,  tabular,  or  acicular  in  habit  (Figs.  52  to  57);  rarely  twins; 
cleavable,  granular,  stalactitic,  oolitic,  earthy.  Cleavage  perfect,  three  direc- 
tions at  75°  and  105°  (lOll);  brittle;  fracture  conchoidal,  seldom  observed. 

Color  white,  colorless,  pale  shades  of  gray,  yellow,  red,  green,  blue,  violet; 
brown  to  black  when  impure.  Streak  white.  Luster  vitreous,  dull.  Trans- 
parent to  opaque.  (See  p.  246.) 

Chief  constituent  of  limestone,  marble,  chalk,  calcareous  marl;  in  veins 
with  metallic  ores,  quartz,  pyrite,  zeolites.  For  varieties,  see  p.  40. 

3      G.  6.1-6.4    ANGLESITE  (Lead  Vitriol),  PbSO4;   Pb  68.3%. 

Struct. — Orthorhombic  crystals;  granular,  compact.  Cleavage  three 
directions  at  76°,  90°,  and  104°  (001)  (110),  not  conspicuous;  brittle;  fracture 
conchoidal. 

Color  white,  colorless,  gray,  brown,  green.  Streak  white.  Luster  adaman- 
tine, vitreous.  Transparent  to  translucent.  (See  p.  214.) 

In  oxidized  parts  of  ore  deposits  with  lead,  zincrand  iron  minerals. 

3      G.  2.9-3.0    ANHYDRITE  (Anhydrous  Gypsum),  CaSO4 
3%        Struct. — Granular,    compact,    fibrous,    cleavable;     rarely  orthorhombic 
crystals.     Cleavage  distinct,  three  directions  at  90°  (001)  (100)  (010);  brittle; 
fracture  conchoidal. 

Color  white,  grayish,  bluish,  reddish  to  brick-red.     Streak  white  to  grayish. 
Luster  vitreous;   pearly  on  (001).     Translucent  to  opaque.     (See  p.  226.) 
In  limestones,  shales,  salt  deposits;  with  halite,  gypsum,  calcite. 


66  -  DETERMINATIVE  MINERALOGY  [SEC.  11 


G.  2.8-2.9    DOLOMITE,  CaMg(CO3)2;  sometimes  FeandMn;  much  Fe, 

Ankerite. 

Struct.  —  Granular,  cleavable,  compact;  hexagonal-rhombohedral  crystals, 
faces  often  curved  (pearl  spar).  Cleavage  perfect,  three  directions  at  74°  and 
106°  (1011);  brittle;  fracture  conchoidal,  uneven. 

Color  white,  colorless,  gray,  red,  green,  brown,  black.  Streak  white. 
Luster  vitreous,  pearly.  Transparent  to  opaque.  (See  p.  246.) 

Extensive  strata  as  dolomitic  limestone  and  marble;  gangue  with  ores  of 
lead,  zinc,  etc.;  with  serpentine,  talc,  gypsum,  and  ordinary  limestones. 

G.  3.8-3.9  SIDERITE  (Spathic  Iron,  Chalybite,  Clay  Ironstone,  Black 
Band  Ore),  FeCO3;  Fe  48.3%. 

Struct.  —  Granular,  cleavable,  compact;  hexagonal  rhombohedral  crystals, 
curved  and  saddle-shaped  common.  Cleavage  perfect,  three  directions  at 
73°  and  107°  (lOll);  brittle;  fracture  uneven. 

Color  gray,  yellow,  brown,  black,  sometimes  white.  Streak  white,  pale 
yellow.  Luster  vitreous,  pearly,  dull.  Translucent  to  opaque.  (See  pp. 
218,  248.) 

In  veins  with  silver  minerals,  pyrite  and  other  sulphides,  cryolite;  beds 
and  concretions  in  limestone,  shale,  and  coal. 

G.  2.9-3.0    ARAGONITE  (Flos  Ferri),  CaCO3;  sometimes  Sr  and  Pb. 

Struct.  —  Chisel-  or  spear-shaped  orthorhombic  crystals,  pseudohexagonal 
prisms;  acicular,  columnar,  stalactitic,  coral-like.  Cleavage  three  directions 
at  64°,  90°,  and  116°  (110)  (010);  brittle;  fracture  conchoidal. 

Color  white,  gray,  yellow,  pale  green,  violet.  Streak  white.  Luster 
vitreous,  resinous.  Transparent  to  translucent.  (See  p.  246.) 

In  gypsum  beds,  basalt,  serpentine,  beds  of  limonite  and  siderite;  with 
celestite,  sulphur,  metallic  sulphides,  zeolites;  constitutes  some  shells 
(pearly  layers  of  many)  and  coral. 

G.  3.9-4.1  SPHALERITE  (Blende,  Zinc  Blende,  Jack,  Black  Jack,  Rosin 
Jack),  ZnS;  Zn  67%;  may  be  replaced  by  Fe  up  to  18%. 

Struct.  —  Cleavable  masses,  granular,  compact,  botryoidal;  rounded 
isometric-tetrahedral  crystals.  Cleavage  pronounced,  six  directions  at  60°, 
90°,  and  120°  (110);  brittle;  fracture  conchoidal. 

Color  yellow,  brown,  red,  green,  black;  rarely  white  or  pale  gray  (cleio- 
phane).  Streak  white,  light  to  dark  brown.  Luster  resinous,  adamantine, 
submetallic.  Transparent  to  opaque.  (See  pp.  200,  228,  250.) 

Ore  deposits  and  veins  with  galena,  pyrite,  chalcopyrite,  fluorite,  barite; 
also  in  limestones. 


4  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  M£iO6,  or  (AlO)2SiO3. 

5  Struct.  —  Long  tabular  or  bladed  triclinic  crystals  without  terminations; 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  length- 
wise at  74°  and  106°  (100)  (010);  transverse  parting  (001)  common;  brittle; 
fracture  splintery. 


SEC.  11]  PHYSICAL  TABLES  67 

H. 

Color  blue,  white,  gray,  green,  nearly  black;  often  streaked.  Streak 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  pp.  256,  260.) 

Hardness  lengthwise  4-5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum. 

5  G.  3.2-3.6    PYROXENE,     Ca(Mg,Fe)(SiO3)2,     ranging     from     Diopside, 

6  CaMg(SiO3)2,   to    Hedenbergite,  CaFe(SiO3)2;    often  some 
Al,  Mn,  and  Na. 

AUGITE  (a  pyroxene),  like  common  pyroxene  above,  with 
A12O3  up  to  15%  or  20%;  sometimes  Na  and  K. 

Struct. — Granular,  columnar,  rarely  fibrous;  lamellar  (diallage);  thick 
monoclinic  prisms  four-  or  eight-sided  (Figs.  40,  41).  Cleavage  two  directions 
lengthwise  at  87°  and  93°  (110),  sometimes  distinct;  often  prominent  parting 
crosswise  (001);  diallage  has  fine  lamellar  parting  one  direction  lengthwise 
(100);  brittle;  fracture  uneven. 

Color  bright  to  dark  green,  grayish  green,  black,  brown.  Streak  greenish, 
brownish,  grayish  to  white.  Luster  vitreous,  submetallic,  dull.  Transparent 
to  opaque.  (See  pp.  220,  222,  240.) 

Common  in  basic  igneous  rocks;  in  crystalline  limestones  with  garnet, 
chlorite,  amphibole,  wollastonite,  magnetite,  pyrite. 

5  G.  3.2-3.6     DIOPSIDE  (Malacolite,  a  pyroxene),  CaMg(SiO3)2;  some  Fe. 

6  Struct. — Prismatic  monoclinic  (pseudotetragonal)  crystals,  stout,  termi- 
nated (Figs.  40,  41);   lamellar,  granular,  compact.     Cleavage  two  directions 
lengthwise  at  87°  and  93°  (110)  sometimes  distinct;  often  conspicuous  trans- 
verse parting  (001);  brittle;  fracture  uneven. 

Color  white,  colorless,  grayish,  green  to  black.  Streak  white,  grayish, 
greenish.  Luster  vitreous,  dull.  Transparent  to  opaque.  (See  p.  240.) 

In  basic  igneous  rocks;  in  crystalline  limestones  with  wernerite,  vesuvian- 
ite,  garnet. 

5  G.  2.5-2.6    NEPHELITE  (Nepheline,  Elaeolite,  a  feldspathoid),  NaAlSiO*; 

6  also  K  (up  to  7%  K2O). 

Struct. — Compact,  disseminated  grains;  small  hexagonal  crystals  rare; 
Cleavage  distinct,  three  directions  at  60°  and  120°  (lOll);  brittle;  fracture 
conchoidal,  uneven. 

Color  reddish,  brownish,  greenish,  gray,  white,  colorless.  Streak  white. 
Luster  greasy,  vitreous.  Transparent  to  opaque.  (See  p.  232.) 

In  lavas  and  granular  igneous  rocks  with  feldspars,  sodalite,  cancrinitej 
biotite,  zircon,  corundum;  not  with  quartz. 

5  G.  3.3-3.5    HYPERSTHENE  (a  pyroxene),  (Fe,Mg)SiO3;  sometimes  Al. 

6  Struct. — Foliated,     cleavable,     granular;      orthorhombic    crystals    rare. 
Cleavage  perfect,  one  direction  (010),  less  distinct  in  two  directions  (110),  at 
46°,  88°,  92°,  134°;  brittle;  fracture  uneven. 

Color  grayish,  greenish,  and  brownish  black  to  bronze.  Streak  brownish 
gray,  grayish  white.  Luster  metalloidal,  bronzy,  pearly.  Opaque  to  trans- 
lucent. (See  pp.  222,  258.) 

In  basic  igneous  rocks  with  plagioclase  feldspars,  olivine,  amphibole, 
pyroxene,  magnetite,  titanite;  seldom  with  quartz. 


68  DETERMINATIVE  MINERALOGY  [SEC.  11 

H. 

5  G.  2.4-2.5    CANCRINITE  (a  feldspathoid),  H6Na6Ca(NaCO3)2Al8(SiO4)9. 

6  Struct.  —  Compact,  lamellar,  columnar,  disseminated;  prismatic  hexagonal 
crystals  rare.     Cleavage  distinct,  three  directions  at  60°  and  120°  (lOlO); 
brittle;  fracture  uneven. 

Color  white,  gray,  yellow,  green,  blue,  reddish.  Streak  white.  Luster 
vitreous,  greasy,  pearly.  Transparent  to  translucent.  (See  p.  230.) 

In  granular  igneous  rocks  with  nephelite,  sodalite,  biotite,  feldspars, 
titanite;  not  with  quartz. 

5|    G.  3.8-3.9    Octahedrite  (Anatase),  Ti02;   Ti  60%. 

6  Struct.  —  Tetragonal  crystals,  pyramidal,  tabular,  rarely  prismatic.  Cleav- 
age distinct,  five  directions  at  82°,  111°,  and  136|°  (111)  (001);  brittle;  frac- 
ture uneven. 

Color  brown,  dark  blue,  black.  Streak  white,  pale  gray.  Luster  adaman- 
tine, metallic.  Translucent  to  opaque.  (See  pp.  210,  262.) 

Minute  crystals  in  granular  igneous  rocks;  in  gneiss,  schists,  quartzite, 
limestone;  with  brookite,  rutile,  ilmenite,  biotite,  adularia,  titanite,  gold. 

5|    G.  4.0  Perovskite  (Perofskite),  CaTiO3;  some  Fe. 

6  Streak.  —  Isometric  (or  pseudoisometric)  crystals,  commonly  cubes  (Fig. 
5),  often  highly  modified  and  striated;  reniform  aggregates,  rounded  grains; 
Cleavage  distinct,  three  directions  at  90°  (100);  brittle;  fracture  uneven. 

Color  pale  yellow  to  orange-yellow,  reddish  brown,  grayish  black.  Streak 
white,  grayish.  Luster  adamantine,  submetallic.  Transparent  to  opaque. 
(See  pp.  210,  258.) 

In  schists,  crystalline  limestone,  serpentine,  basic  igneous  rocks;  with 
chlorite,  magnetite,  garnet,  vesuvianite,  rutile,  ilmenite,  corundum. 


6  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  Al2SiO5,  or 

7  Struct.  —  Long  tabular  or  bladed  triclinic  crystals  without  termination; 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  length- 
wise at  74°  and  106°  (100)  (010);  transverse  parting  (001)  common;  brittle; 
fracture  splintery. 

Color  blue,  white,  gray,  green,  nearly  black;  often  streaked.  Streak 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  pp.  256,  260.) 

Hardness  lengthwise  4-5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum. 

6£     G.  3.4-4.3    GARNET,  R3"R2'"(SiO4)3;    R"=Ca,  Mg,  Fe,  Mn;   R'"=A1, 

7|  Fe,  Cr,  sometimes  Ti. 

Struct.  —  Isometric  crystals  (dodecahedrons,  trapezohedrons,  Figs.  3,  7, 
8);  granular,  lamellar,  compact,  disseminated,  sand.  Cleavage  none;  parting 
sometimes  distinct,  six  directions  at  60°,  90°,  and  120°  (110);  brittle;  fracture 
conchoidal,  uneven. 

Color  red,  brown,  black,  green,  purple,  etc.  (See  varieties,  p.  101.)  Streak 
white.  Luster  vitreous.  Transparent  to  opaque.  (See  p.  244.) 

For  varieties  and  occurrence,  see  p.  101. 


SECS.  11,  12]  PHYSICAL  TABLES  69 

H. 

9  G.  3.9-4.1     CORUNDUM  (Adamantine  Spar),  A1203. 

Struct. — Rough  hexagonal-rhombohedral  crystals,  prismatic,  pyramidal, 
tabular,  tapering  (barrel-shaped),  often  striated;  lamellar,  granular,  compact. 
Cleavage  none;  often  conspicuous  parting  three  directions  at  86°  and  94° 
(lOll);  sometimes  transverse  parting  (0001);  brittle,  tough  when  compact; 
fracture  uneven,  conchoidal. 

Color  white,  gray,  brown,  to  black;  deep  red  (ruby);  blue  (sapphire); 
black  from  admixture  of  magnetite,  hematite,  or  spinel  (emery).  Streak 
white.  Luster  vitreous,  adamantine.  Transparent  to  opaque.  (See  p.  260.) 

In  peridotite,  gneiss,  schist,  syenite,  crystalline  limestone;  with  olivine, 
chlorite,  serpentine,  magnetite,  spinel,  vermiculite;  cyanite,  diaspore,  musco- 
vite. 

10  G.3.5  DIAMOND  (Carbon),  C. 

Struct. — Isometric  crystals  (octahedron,  hexoctahedron,  Figs.  1,  4)  usually 
with  curved  surfaces;  rounded  and  irregular  grains,  pebbles,  often  with  radial 
structure.  Cleavage  distinct,  four  directions  at  70|°  and  109£°  (111);  brittle; 
fracture  conchoidal. 

Color  white,  colorless,  pale  shades  of  yellow,  red,  orange,  green,  blue, 
brown;  occasionally  black.  Streak  white.  Luster  adamantine,  greasy. 
Transparent  to  opaque.  Bort,  rough  rounded  masses  with  radial  or  confused 
crystalline  structure,  without  distinct  cleavage;  grayish  to  black;  sp.  g.  3.5. 
Carbonado,  or  black  diamond,  granular  to  compact,  without  cleavage;  sp.  g. 
3.1-3.3.  (See  p.  264.) 

In  peridotite  or  serpentine;  in  sands,  gravels,  quartzite;  with  pyrope, 
magnetite,  chromite,  zircon,  gold. 


SECTION  12 

Streak  chalk-white,  colorless,  or  pale  colored;  mineral  dark  gray 
to  black;  no  distinct  cleavage. 

1      G.  5.5-5.6    CERARGYRITE  (Horn  Silver),  AgCl;  Ag  75.3%;  sometimes  Hg. 
If        Struct. — Wax-like  crusts,  stalactitic,  dendritic;   isometric  (cubic)  crystals 
rare.     Cleavage  none;   highly  sectile;  fracture  conchoidal. 

Color  pearly  gray,  greenish,  colorless;  turns  violet,  brown  to  black  on 
exposure  to  light.  Streak  white,  grayish,  shiny.  Luster  waxy,  greasy, 
resinous.  Transparent  to  translucent.  (See  p.  216.) 

In  veins  with  other  silver  minerals,  calcite,  barite,  limonite. 

1  G.  2.2-2.4    GLAUCONITE  (Greensand,  Green  Earth),  approx.  KFe(SiO3)2  •  H2O ; 

2  K2O  6.9%;  some  Al  and  Mg. 

Struct. — Granular,  earthy,  disseminated;  amorphous.  Cleavage  none; 
brittle;  fracture  earthy,  uneven. 

Color  yellowish  green,  grayish  green,  blackish  green.  Streak  light  green, 
greenish  white.  Luster  vitreous,  dull.  Opaque.  (See  p.  220.) 

Abundant  in  greensand  beds  (so-called  marls);  disseminated  in  sands, 
clays,  sandstones,  limestones. 


70  DETERMINATIVE  MINERALOGY  [SEC.  12 

H. 

1  G.  0.9-1.0    OZOCEKITE  (Mineral  Wax,  Native  Paraffin),  CBH2n+2. 

2  Struct.  —  Amorphous,  compact,  fibrous,  lamellar;   plastic;   may  be  sticky. 
Color  black,  brownish  black,  brownish  yellow,  leek-green.     Streak  yellow- 

ish brown,  pale  yellow.    Luster  waxy,  greasy,  submetallic.     Translucent, 
sometimes  greenish  opalescence.     (See  p.  212.) 

Like  wax  ;  greasy  feel  .  Burns  with  bright  smoky  flame  and  odor  of  paraffin  . 
In  veins  in  sedimentary  rocks. 

1  G.  6.4-6.5    Calomel  (Horn  Quicksilver),  HgjCU;  Hg  84.9%. 

2  Struct.  —  Coatings;  small  tetragonal  crystals,  tabular,  pyramidal.     Cleav- 
age indistinct,  two  directions  (100)  at  90°;  sectile;  fracture  conchoidal. 

Color  white,  gray,  yellowish  to  brown.      Streak  white,  gray,  yellowish. 
Luster  adamantine.     Translucent  to  opaque.     (See  p.  212.) 
In  veins  with  cinnabar  and  mercury. 

2      G.  2.6-2.7     Pharmacolite  (Arsenic  Bloom),  HCaAsO4-2H2O. 
58^        Struct.  —  Fibrous,  acicular,  incrusting,  powdery;    small  prismatic  mono- 
clinic  crystals  rare.    Cleavage  distinct,  one  direction  lengthwise  (010);  sectile; 
thin  flakes  flexible;  fracture  uneven. 

Color  white,  grayish;  may  be  tinged  red  by  Co  or  green  by  Ni.     Streak 
white.     Luster  vitreous,  pearly.     Translucent  to  opaque.     (See  p.  228.) 
With  arsenopyrite  and  arsenical  ores  of  cobalt  and  silver. 

2  G.  5.2-5.3    Senarmontite,  Sr>2O3;  Sb  83.3%. 

2|  Struct.  —  Isometric  crystals  (octahedrons,  ,Fig.  1);  granular,  incrusting. 
Cleavage  indistinct;  brittle;  fracture  uneven. 

Color  white,  colorless,  grayish.  Streak  white.  Luster  greasy,  pearly. 
Transparent  to  translucent.  (See  p.  212.) 

With  stibnite  and  other  antimony  minerals. 

3  G.  6.4-6.6    CERUSITE  (White  Lead  Ore),  PbCO3;   Pb  77.5%. 

3f  Struct.  —  Pseudohexagonal  orthorhombic  crystals,  clusters,  star-shaped 
groups;  granular,  fibrous,  compact.  Cleavage  indistinct;  brittle;  fracture 
conchoidal. 

Color  white,  gray,  colorless;  or  yellow,  brown,  etc.,  from  impurities. 
Streak  white.  Luster  adamantine,  greasy,  silky.  Transparent  to  trans- 
lucent. (See  p.  214.) 

In  oxidized  parts  of  lead  ores  with  lead,  zinc,  iron,  and  copper  minerals. 


3  G.  2.5-2.6    SERPENTINE,  BUMgaSiaOsj    commonly  Fe,  sometimes  Ni. 

4  Struct.  —  Massive  compact,  fibrous  (chrysotile,  asbestos)',    lamellar  (mar- 
molile)',    columnar  (picrolite)  ;    brittle;    fibers  flexible  and  tough;    fracture 
conchoidal,  splintery. 

Color  olive-green,  blackish  green,  yellowish  green,  yellow;  rarely  white. 
Streak  white.  Luster  greasy,  waxy,  silky.  Translucent  to  opaque.  (See 
pp.  232,  254.) 

Common  alteration  product  of  olivine  rocks  (peridotites)  ;  in  dolomitic 
limestone;  with  magnesite,  talc,  chromite,  magnetite,  corundum,  platinum, 
diamond.  Mixed  with  dolomite,  calcite,  or  magnesite  in  a  mottled  or  clouded 
green  marble  (verdantique,  or  ophicalcite)  . 


SEC.  12]  PHYSICAL  TABLES  71 

3  G.  4.3-4.4    WITHERITE,  BaCO3;  BaO  77.7%. 

4  Struct. — Compact,   granular,  radial  fibrous,   lamellar;    pseudohexagonal 
orthorhombic    crystals    resembling    quartz.     Cleavage    indistinct;     brittle; 
fracture  uneven. 

Color  white,  grayish,  yellowish.     Streak  white.    Luster  vitreous,  greasy. 
Transparent  to  translucent.     (See  p.  226.) 
In  veins  with  galena,  barite,  fluorite,  calcite. 

3i    G.  6.5-7.1    PYROMORPHITE  (Green  Lead  Ore),  Pb5Cl(P04)3;  Pb  76.3%; 
4  P205 15.7%. 

Struct. — Small  prismatic  hexagonal  crystals,  often  rounded,  barrel- 
shaped,  sometimes  hollow;  incrusting,  reniform,  disseminated.  Cleavage 
none;  brittle;  fracture  conchoidal,  uneven. 

Color  green,  yellow,  brown,  white,  gray.  Streak  pale  yellow,  greenish 
yellow,  white.  Luster  resinous,  greasy,  adamantine.  Translucent  to  opaque. 
(See  p.  214.) 

In  oxidized  parts  of  lead  veins  with  galena,  cerusite,  mimetite,  barite, 
limonite. 

3£    G.  3.1-3.3    SCORODITE,  FeAsO4-2H2O. 

4  Struct. — Pyramidal  orthorhombic  crystals,  sometimes  prismatic  or  tab- 
ular; botryoidal,  fibrous,  earthy,  amorphous.     Cleavage  imperfect,  two  direc- 
tions at  60°  and  120°  (120);  brittle;  fracture  conchoidal,  uneven. 

Color  pale  green,  bluish  green,  blackish  green,  blue,  brown.  Streak 
white,  grayish,  greenish.  Luster  vitreous,  greasy.  Translucent.  (See  p. 
218.) 

With  arsenopyrite,  enargite,  limonite,  pyrite. 

5  G.  2.1-2.3    SODALITE  (a  feldspathoid),  Na4Al3Cl(SiO4)3. 

6  Struct. — Compact,    disseminated    grains,    nodular;     isometric    crystals 
(dodecahedrons)  rare.     Cleavage  indistinct,  six  directions  at  60°,  90°,  and 
120°  (110);   brittle;   fracture  conchoidal,  uneven. 

Color  blue,  gray,  white,  red,  green.  Streak  white.  Luster  vitreous, 
greasy.  Transparent  to  translucent.  (See  p.  230.) 

In  igneous  rocks  with  nephelite,  leucite,  cancrinite;   not  with  quartz. 

5|    G.  2.4-2.5    LEUCITE  (Amphigene,  a  feldspathoid),  KAl(SiO3)2;  K2O  21.5%. 
6          Struct. — Isometric  crystals  (trapezohedrons,  Fig.  3) ;  rounded  disseminated 
grains.     Cleavage  indistinct;   brittle;   fracture  conchoidal. 

Color  white,  gray,  yellowish,  reddish,  colorless.  Streak  white.  Luster 
vitreous,  greasy.  Translucent  to  opaque.  (See  p.  254.) 

In  lavas  with  sanidine,  augite,  nephelite,  olivine;  not  with  quartz. 

5|     G.  3.0-4.2     ALLANITE  (Orthite),  (Ca,Fe)2(Al,Fe,Ce)3OH(SiO4)3;  also  La,  Nd, 

6  Pr,  Y. 

Struct. — Compact,  granular,  bladed,  disseminated;  rough  tabular  mono- 
clinic  crystals  rare.  Cleavage  indistinct;  brittle;  fracture  conchoidal,  un- 
even. 


72  DETERMINATIVE  MINERALOGY  [SEC.  12 

H. 

Color  brownish  black,  pitch  black.  May  be  coated  with  yellowish  or 
brownish  alteration  product.  Streak  pale  gray,  greenish,  brownish.  Luster 
metallic,  submetallic,  pitchy,  vitreous.  Translucent  to  opaque.  (See  pp.  206, 
220,  232.) 

Minor  accessory  in  the  acid  igneous  rocks  with  magnetite,  epidote,  quartz, 
feldspars;  also  in  limestones. 

5|     G.  3.9-^.1     Brookite  (Arkansite),  Ti02;    Ti  60%. 

6  Struct. — Orthorhombic  crystals,  often  tabular  (pseudohexagonal),  also 
prismatic,  faces  often  striated.  Cleavage  indistinct;  brittle;  fracture  un- 
even. 

Color  hair-brown,  yellowish  and  reddish  brown  to  iron-black.  Streak 
white,  grayish,  yellowish,  brownish.  Luster  adamantine,  metallic.  Opaque. 
(See  pp.  210,  262.) 

In  igneous  rocks,  gneiss,  crystalline  limestone;  in  veins  with  quartz, 
feldspars,  metallic  sulphides;  with  rutile,  octahedrite,  titanite,  adularia, 
nephelite;  in  gold  placers. 

5|    G.  4.3-5.8    Fergusonite,  (Y,Er,Ce,U)(Cb,Ta)O4;  some  Ca,  Fe,  H2O. 
6          Struct. — Disseminated,    compact;     pyramidal    tetragonal    crystals   rare. 
Cleavage  none;   brittle;   fracture  conchoidal,  uneven. 

Color  brownish  black,  brown.  Streak  pale  brown.  Luster  submetallic, 
vitreous;  often  dull  outside.  Translucent  to  opaque.  (See  pp.  210,  264.) 

Brilliant  luster  of  fresh  fracture  in  striking  contrast  with  dull  surface.  In 
granite  and  pegmatite  with  quartz,  feldspars,  zircon,  allanite,  gadolinite;  in 
placer  gravels. 

5|    G.  2.1-2.2    OPAL,  Si02 -nH20  ;  H20  2-16%;  chiefly  3-9%. 
6£        Struct. — Amorphous,  botryoidal,  reniform,  stalactitic,  earthy.     Cleavage 
none;  brittle;  fracture  conchoidal,  conspicuous  when  compact. 

Color  white,  yellow,  red,  brown,  green,  gray,  blue,  colorless;  sometimes  a 
rich  play  of  colors  (precious  opal).  Streak  white.  Luster  vitreous,  pearly, 
dull.  Transparent  to  opaque.  (See  pp.  256,  260,  264.) 

In  cavities  and  veins  in  igneous  and  sedimentary  rocks.  For  varieties 
see  p.  54. 

6      G.  2.8-3.0    PREHNITE,  H2Ca2Al2(SiO4)3. 

62  Struct. — Botryoidal,  stalactitic,  radial  fibrous;  rounded  groups  of  tabular 
orthorhombic  crystals;  distinct  crystals  rare.  Cleavage  indistinct,  one  direc- 
tion (001);  brittle;  fracture  uneven. 

Color  light  green,  oil-green,  gray,  white;  often  fading  on  exposure.  Streak 
white.  Luster  vitreous,  waxy.  Transparent  to  translucent.  (See  pp.  234, 
244.) 

With  zeolites,  datolite,  apophyllite,  pectolite,  native  copper,  calcite,  quartz, 
epidote,  chlorite — in  igneous  rocks,  chiefly  basic. 

6  G.  4.1^.3    RUTILE  (Nigrine),  TiO2;   Ti  61%;   often  Fe. 

7  Struct. — Prismatic  tetragonal  crystals  striated  lengthwise;    knee-shaped 
and  rosette  twins;    acicular,  compact,  disseminated.     Cleavage  indistinct; 
brittle;   fracture  uneven. 


SEC.  12]  PHYSICAL  TABLES  73 

H. 

Color  red,  reddish  brown,  black  (deep  red  when  transparent).  Streak 
white,  gray,  pale  brown.  Luster  metallic,  adamantine.  Transparent  to 
opaque.  (See  pp.  210,  262.) 

In  veins  with  quartz,  feldspars,  hematite,  ilmenite;  hair-like  inclusions 
in  quartz;  in  igneous  contacts  and  metamorphic  rocks. 

6  G.  6.8-7.1     CASSITERITE  (Tinstone),  SnO2;    Sn  78.6%;    sometimes  Fe 

7  and  Ta. 

Struct. — Granular,  disseminated,  reniform  with  radiating  fibrous  structure 
(wood  tin),  sand  and  pebbles  (stream  tin);  thick  prismatic  tetragonal  crystals, 
knee-shaped  twins  common  (Fig.  29).  Cleavage  indistinct;  brittle;  fracture 
uneven. 

Color  brown  to  black,  rarely  yellow,  red,  gray,  white.  Streak  white, 
grayish,  brownish.  Luster  adamantine,  greasy,  dull.  Transparent  to  opaque. 
(See  p.  262.) 

In  granite,  gneiss,  with  wolframite,  scheelite,  molybdenite,  tourmaline, 
fluorite,  topaz,  apatite,  lepidolite;  in  pegmatites;  in  sands  and  gravels. 

6  G.  4.0-4.5    Gadolinite,  FeGl2(YO)2(SiO4)2;  some  Ce,  La,  Nd,  Pr,  Er,  Sc,  etc. 

7  Struct. — Compact,    disseminated,   nodular;    rough  prismatic  monoclinic 
crystals  rare.     Cleavage  none;   brittle;   fracture  conchoidal,  splintery. 

Color  black,  greenish  black,  brown;  thin  splinters  grass-green  to  olive- 
green.  Streak  greenish  gray.  Luster  vitreous,  greasy.  Translucent  to 
opaque.  (See  pp.  232,  252.) 

In  granite  and  pegmatite  with  quartz,  mica,  allanite,  fergusonite,  fluorite, 
molybdenite. 

6J     G.  3.4-4.3    GARNET,    R3"R/"(SiO4)3;       R"=Ca,  Mg,    Fe,     Mn,    Ti; 
7^  R"'=A1,  Fe,  Cr,  Ti. 

Struct. — Isometric  crystals  (dodecahedrons,  trapezohedrons,  Figs.  3,  7,  8); 
granular,  lamellar,  compact,  disseminated,  sand.  Cleavage  none;  parting, 
sometimes  distinct,  six  directions  at  60°,  90°,  120°  (110);  brittle;  fracture  con- 
choidal, uneven. 

Color  red,  brown,  black,  etc.  (see  varieties  p.  101).    Streak  white.  Luster 
vitreous.     Transparent  to  opaque.     (See  p.  244.) 
For  occurrence  and  varieties,  see  p.  101. 

7      G.  2.65         QUARTZ  (Rock  Crystal),  Si02. 

Struct. — Prismatic  hexagonal  crystals  striated  crosswise,  commonly 
terminated  by  double  rhombohedron  (like  hexagonal  pyramid);  granular, 
disseminated,  compact.  Cleavage  indistinct;  brittle;  fracture  conchoidal. 

Color  white,  colorless,  and  various  shades  to  black  (see  varieties,  p.  55). 
Streak  white.  Luster  vitreous,  greasy.  Transparent  to  opaque.  (See  p. 
262.) 

In  igneous  rocks,  gneiss,  schists,  sand,  sandstone,  quartzite;  common 
vein  mineral  with  many  metallic  ores. 


74  DETERMINATIVE  MINERALOGY  [SBC.  12 

H. 

7      G.  2.6-2.64    CHALCEDONY  (Agate,  Flint,  Hornstone),  SiO2. 

Struct. — Compact,  botryoidal,  mammillary,  banded.  Cleavage  none; 
brittle  to  tough;  fracture  conchoidal. 

Color  white,  grayish,  brownish  to  black  (see  varieties,  p.  55).  Streak 
white.  Luster  waxy,  vitreous,  to  nearly  dull.  Translucent  to  opaque. 
(See  p.  262.) 

Lining  or  filling  cavities  (agate,  etc.);  concretions  in  chalk  (flint)  or  lime- 
stone (chert,  hornstone). 

7  G.  3.0-3.2  TOURMALINE,  R9Al3(BOH)2(SiO5)4;  R  =  Mg,  Fe,  Ca,  Na, 
n  K,  Li. 

Struct.  —  Prismatic  hexagonal-rhombohedral  crystals,  hemimorphic, 
curved  triangular  in  cross-section,  striated  lengthwise  (Fig.  58);  radiating, 
columnar,  compact.  Cleavage  indistinct;  brittle;  fracture  uneven,  conchoidal. 

Color  black  (schorl),  blue  (indicolite) ,  pink  to  red  (rubellite),  brown,  green; 
rarely  white  or  colorless  (achroite).  Streak  white.  Luster  vitreous,  resinous. 
Transparent  to  opaque.  (See  pp.  222,  242,  258.) 

In  pegmatite,  gneiss,  mica  schist,  slate,  gravels;  common  at  contacts; 
with  quartz,  feldspars,  beryl,  topaz,  cassiterite,  fluorite. 

7  G.  3.6-3.8  STAUROLITE  (Staurotide),  Fe(AlO)4(AlOH)(SiO4)2;  some- 
7f  times  Mg,  Mn. 

Struct. — Prismatic  orthorhombic  crystals;  cross  twins  at  60°  and  90° 
common  (Figs.  31  to  33);  often  rough.  Cleavage  not  conspicuous,  one  direc- 
tion lengthwise  (010):  brittle;  fracture  conchoidal,  uneven. 

Color  yellowish  brown,  reddish  to  brownish  black,  weathering  gray. 
Streak  white  to  grayish.  Luster  vitreous,  dull.  Translucent  to  opaque. 
(See  p.  260.) 

In  slate,  schists,  gneiss,  with  garnet,  cyanite,  sillimanite,  tourmaline. 

7J     G.  4.5-4.8    ZIRCON,  ZrSiO4;   ZrO  67.2%;   commonly  a  little  Fe. 

Struct. — Square  tetragonal  crystals  with  prism  and  pyramid;  irregular 
lumps,  disseminated  grains;  Cleavage  indistinct;  brittle;  fracture  uneven. 

Color  gray,  brown,  yellow,  green;  red  transparent  (hyacinth);  colorless  or 
smoky  (jargon).  Streak  white.  Luster  adamantine,  vitreous.  Opaque  to 
transparent.  (See  p.  262.) 

Minute  grains  in  feldspathic  igneous  rocks;  rare  in  crystalline  limestone, 
gneiss,  schist;  with  magnetite,  apatite,  biotite,  wollastonite,  titanite;  in 
placers  with  gold,  corundum,  spinel,  garnet,  monazite. 

7£     G.  3.6-4.6    SPINEL,  MgAl2O4;   also  Fe,  Mn,  Cr,  Zn— see  varieties  below. 
8£        Struct. — Isometric   crystals    (octahedrons,    Fig.    1);    granular,    compact, 
disseminated.     Cleavage  indistinct;   brittle;   fracture  conchoidal. 

Color  red,  yellow,  green,  blue,  brown,  black  (see  varieties,  p.  127).     Streak 
white.     Luster  vitreous,  dull.     Transparent  to  opaque.     (See  p.  262.) 
For  varieties  and  occurrence,  see  p.  127. 


SECS.  12,  13]  PHYSICAL  TABLES  73 

H. 

9      G.  3.9-4.1     CORUNDUM  (Adamantine  Spar),  A1203. 

Struct. — Rough  hexagonal-rhombohedral  crystals,  prismatic,  pyramidal, 
tabular,  tapering  (barrel-shaped),  often  striated;  lamellar,  granular,  compact. 
Cleavage  none;  often  conspicuous  parting  three  directions  at  86°  and  94° 
(lOll);  sometimes  transverse  parting  (0001);  brittle,  tough  when  compact; 
fracture  uneven,  conchoidal. 

Color  white,  gray,  brown,  to  black;  deep  red  (ruby);  blue  (sapphire); 
black  from  admixture  of  magnetite,  hematite,  or  spinel  (emery).  Streak 
white.  Luster  vitreous,  adamantine.  Transparent  to  opaque.  (See  p.  260.) 

In  peridotite,  gneiss,  schist,  syenite,  crystalline  limestone;  with  olivine, 
chlorite,  serpentine,  magnetite,  spinel,  vermiculite;  cyanite,  diaspore,  musco- 
vite. 

SECTION  13 

Streak  chalk- white,  colorless,  or  pale  colored;  mineral  yellow,  red, 
or  brown;   distinct  cleavage  one  direction  only. 

0  G.  1.4-1.5    Sassolite  (Native  Boric  Acid),  H3BO3;   B2O3  56.4%. 

1  Struct. — Small  pearly  scales;  rarely  thin  tabular  triclinic  crystals.     Cleav- 
age perfect,  one  direction  (001);   greasy  feel;   brittle. 

Color  white,  grayish,  yellowish.  Streak  white.  Luster  pearly.  Trans- 
lucent. Acid  taste.  (See  p.  228.) 

In  hot  lagoons,  fumaroles,  volcanic  craters,  lakes,  springs. 

1       G.  2.3-2.8     VERMICULITE  (Jeffersite,  Culsageeite,  etc.,  "Cat  Gold  ")  Hydrated 
1J  micas  and  chlorites;  silicates  of  Mg,  Fe,  Al. 

Struct. — Scaly,  flaky;  monoclinic  pseudomorphous  crystals.  Cleavage 
perfect,  one  direction  (001);  thin  flakes  flexible — some  very  slightly  so;  not 
elastic. 

Color  golden  yellow,  yellowish  brown,  brownish  red,  yellowish  green,  dark 
green.  Streak  white.  Luster  pearly  to  nearly  dull,  metallic.  Translucent 
to  opaque.  (See  p.  232.) 

With  peridotite,  serpentine,  talc,  chlorite,  corundum,  micas. 

1  2.8-2.9        PYROPHYLLITE  (Pencil  Stone),  H2Al2(SiO3)2. 

2  Struct.  —  Foliated,  granular,  fibrous,  radial,  compact;    indistinct  ortho- 
rhombic  crystals  rare.    Cleavage  perfect,  one  direction  (001);  fracture  uneven, 
splintery;   thin  flakes  flexible,  not  elastic;   feel  greasy. 

Color  white,  apple-green,  gray,  yellow.  Streak  white.  Luster  pearly, 
dull.  Translucent  to  opaque.  (See  p.  256.) 

In  schistose  rocks  with  cyanite,  topaz,  graphite,  lazulite. 

1       G.  2.6-3.1     Kammererite  (Chrome  Chlorite),  H,  Mg,  Fe,  Al  silicate,  with 
31  5-8%  Cr2O3. 

Struct. — Foliated,   scaly,   compact;    pseudohexagonal   monoclinic  plates 

and  pyramidal  crystals.     Cleavage  perfect,  one  direction  (001);    thin  flakes 

flexible,  not  elastic. 


76  DETERMINATIVE  MINERALOGY  [SEC.  13 

H. 

Color  pink,  rose-red,  grayish  red,  violet.  Streak  white.  Luster  pearly. 
Translucent  to  opaque.  (See  pp.  236,  254.) 

In  peridotite  and  serpentine  with  chromite,  other  chlorites,  talc. 

If    G.  2.3-2.4    GYPSUM  (Selenite,  Alabaster,  Satin  Spar),  CaSO4-2H2O. 
2          Struct. — Granular,   foliated,  fibrous;    earthy   (gypsite);    diamond-shaped 
monoclinic  crystals  with  beveled  edges  (Figs.  38,  39).     Cleavage  perfect,  one 
direction  (010),  two  others  less  conspicuous  (111)  (100)  at  90°,  66°,  and  114°; 
brittle;  thin  flakes  flexible;  fracture  conchoidal,  splintery. 

Color  white,  colorless,  gray,  yellow,  red.  Streak  white.  Luster  vitreous; 
pearly  on  (010) ;  silky.  Transparent  to  opaque.  (See  pp.  224,  226.) 

Beds  and  masses  with  limestone,  clay,  shale,  rock  salt;  near  volcanic 
vents;  with  anhydrite,  celestite,  sulphur,  calcite,  aragonite. 

li     G.  2.1  COPIAPITE  (Misy),  Fe4(OH)2(SO4)5-  17H2O;  often  Al  and  Mg. 

2|  Struct. — Granular,  scales,  crusts,  powder;  six-sided  tabular  monoclinic 
crystals  rare.  Cleavage  one  direction  (010) ;  brittle;  fracture  uneven,  scaly, 
earthy. 

Color  yellow  to  greenish  and  brownish  yellow.  Streak  yellowish.  Luster 
pearly,  dull.  Translucent  to  opaque.  Disagreeable  metallic  taste.  (See 
p.  218.) 

With  iron  and  copper  sulphates  from  oxidation  of  sulphides. 

2       G.  2.9-3.0    ROSCOELITE     (Vanadium   Mica),    approx.   H2K(Al,V)3(SiO4)3; 

V2O3  20-29%;  some  Mg,  Fe. 

Struct. — Minute  micaceous  scales.  Color  dark  green  to  brown.  Luster 
pearly.  Translucent.  (See  p.  236. \ 

In  veins  with  quartz,  gold,  and  tellurium;  disseminated  in  sandstone  with 
carnotite. 

2  G.  2.7-3.0     MUSCOVITE  (Common  or  White  Mica,  Potash  Mica,  Isinglass), 

3  H2KAl3(SiO4)3;  often  a  little  Na,  Ca,  Mg,  Fe,  and  F. 
Struct. — Foliated,  flaky;  fine  scaly  to  fibrous  (sericite,  damourite) ;    dense 

•  (pinite);  rarely  distinct  monoclinic  (pseudohexagonal)  crystals.  Cleavage 
perfect,  one  direction  (001) ;  thin  flakes  tough,  very  elastic. 

Color  white,  gray,  yellowish,  greenish,  brownish.  Streak  white.  Luster 
vitreous,  pearly.  Transparent  to  translucent.  (See  p.  236.) 

In  pegmatite,  granite,  gneiss,  schists,  contacts;  with  feldspars,  quartz, 
tourmaline,  beryl,  garnet. 

2  G.  2.8-2.9     Paragonite  (Soda  Mica),  H2NaAl3(SiO4)3. 

3  Fine  scaly  masses,  compact;  strong  pearly  luster.     Otherwise  like  musco- 
vite  above.     In  schists  with  cyanite,  staurolite,  tourmaline,  garnet,  actinolite. 
(See  p.  236.) 

2  G.  2.8-3.1     BIOTITE      (Black     Mica,      Ferromagnesian     Mica 

3  (H,K)2(Mg,Fe)2Al2(SiO4)3;   a  little  F,  often  Ti. 

Struct. — Plates,  scales;  pseudohexagonal  monoclinic  crystals  rare.  Cleav- 
age conspicuous,  one  direction  (001);  thin  flakes  tough,  very  elastic,  becom- 
ir.;;  more  brittle  with  alteration. 


SEC.  13]  PHYSICAL  TABLES  77 

H. 

Color  black,  brownish  black,  greenish  black,  dark  green.  Streak  white. 
Luster  pearly,  submetallic.  Transparent  to  opaque.  (See  pp.  204,  220,  236.) 

Common  in  granite,  syenite,  gneiss,  mica  schist;  less  common  in  basic 
igneous  rocks  and  contacts. 

2  G.  2.8-2.9     PHLOGOPITE  (Amber  Mica,  Bronze  Mica,  Magnesia  Mica), 

3  H2KMgsAl(SiO4)3;   some  F  and  Fe. 

Struct. — Plates,  scales;  prismatic  or  tabular  monoclinic  crystals  with 
hexagonal  or  orthorhombic  outlines,  commonly  rough.  Cleavage  conspicuous, 
one  direction  (001);  thin  flakes  tough,  very  elastic. 

Color  yellowish  brown,  brownish  red,  gray  to  green;  rarely  colorless. 
Streak  white.  Luster  pearly,  submetallic.  Translucent  to  transparent. 
(See  pp.  204,  236.) 

Contacts  in  crystalline  limestone;  in  serpentine;  with  pyroxene,  amphi- 
bole,  serpentine,  graphite,  apatite,  corundum. 

2  G.  2.8-2.9    LEPIDOLITE     (Lithia    Mica),    (Li,K)2Al2(OH,F)2(SiO3)3;     Li2O 

3  3.8-5.8%. 

Struct. — Foliated,  scaly,  compact;  rarely  monoclinic  crystals,  small  tab- 
ular or  prismatic.  Cleavage  perfect,  one  direction  (001);  thin  flakes  tough, 
elastic. 

Color  pink,  lilac,  yellowish,  grayish  white,  white.  Streak  white.  Luster 
pearly.  Translucent.  (See  p.  236.) 

In  pegmatite  with  pink  and  green  tourmaline,  cassiterite,  topaz,  ambly- 
gonite,  spodumene. 

2  G.  2.7  THENARDITE,  Na^SO^  Na^O  56.3%. 

3  Struct. — Orthorhombic  crystals,  often  cross  twins;    granular.     Cleavage 
one  direction  (001) ;  brittle;  fracture  uneven. 

Color  white  to  brownish.     Streak  white.     Luster  vitreous.     Transparent 
to  translucent.     Soluble  in  water.     (See  p.  224). 
About  salt  lakes  and  dry  lake  beds. 

2\    G.  2.7-2.8    Glauberite,  Na2Ca(SO4)2. 

Struct. — Thick  tabular  monoclinic  crystals;  reniform,  lamellar.  Cleavage 
distinct,  one  direction  (001);  brittle;  fracture  conchoidal. 

Color  white,  colorless,  yellowish,  grayish.  White  powdery  coating  forms 
on  exposure.  Streak  white.  Luster  vitreous,  greasy.  Transparent  to  trans- 
lucent. Taste  slightly  salty.  (See  p.  226.) 

With  halite,  thenardite,  mirabilite,  hanksite,  ulexite. 

2k     G.  6.2-6.5     Leadhillite,  Pb4(OH)2(CO3)2SO4. 

Struct. — Tabular  monoclinic  (pseudohexagonal)  crystals  and  twins;  com- 
pact, lamellar.  Cleavage  perfect,  one  direction  (001);  rather  sectile;  fracture 
conchoidal,  rarely  observable. 

Color  white,  colorless,  yellow,  green,  gray.  Streak  white.  Luster  pearly, 
adamantine.  Transparent  to  translucent.  (See  p.  214.) 

Twins  and  trillings  like  aragonite,  but  very  heavy.  Occurs  sparingly 
with  lead  ores. 


78  DETERMINATIVE  MINERALOGY  [SBC.  13 

H. 

2%    G.  2.1-2.2    TRONA  (Urao),  HNa3(C03)2-2H2O. 

3  Struct. — Incrusting;  tabular  or  acicular  monoclinic  crystals.  Cleavage 
one  direction  (100);  brittle;  fracture  uneven. 

Color  white,  colorless,  yellowish,  grayish.  Streak  white.  Luster  vitreous, 
pearly.  Translucent.  Taste  alkaline.  (See  p.  224.) 

Efflorescence;  crusts  on  soda  lakes;  in  beds  with  halite,  glauberite,  mira- 
bilite,  hanksite. 

3|     G.  2.7-2.8     Polyhalite,  K2MgCa2(S04)4-2H2O;   KzO  15.6%. 

3  Struct. — Fibrous,  lamellar,  compact;   monoclinic  (?).     Cleavage  distinct, 
one  direction;  brittle;  fracture  splintery. 

Color  flesh-  to  brick-red;  yellowish  red  to  white.  Streak  white,  reddish 
to  yellowish  white.  Luster  greasy,  pearly.  Translucent  to  opaque.  Taste 
weakly  bitter  and  astringent.  (See  p.  226.) 

In  beds  of  salt,  gypsum,  and  clay. 

2£     G.  2.3-2.4     GIBBSITE  (Hydrargillite),  A1(OH)3. 

3^  Struct. — Stalactitic,  botryoidal,  fibrous  or  scaly  aggregates;  tabular 
monoclinic  (pseudohexagonal)  crystals  rare.  Cleavage  one  direction  (001), 
seldom  observable;  tough. 

Color  white,  grayish,  greenish,  reddish.  Streak  white.  Luster  vitreous, 
pearly,  dull.  Translucent.  (See  p.  256.) 

Chief  constituent  of  some  bauxite  deposits;  with  corundum,  natrolite, 
limonite. 

3|     G.  2.1-2.2    STILBITE  (Desmine,  a  zeolite),  H4(Ca,Na2)Al2(SiO3)6-4H2O. 

4  Struct. — Sheaf-like,  radial,  globular;    tabular  monoclinic  crystals,  com- 
monly in  twinned  groups,  orthorhombic  in  appearance.     Cleavage  distinct, 
one  direction  (010) ;  brittle;  fracture  uneven. 

Color  white,  grayish,  yellowish,  red  to  brown.  Streak  white.  Luster 
vitreous;  pearly  on  cleavage.  Translucent.  (See  p.  234.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous  veins; 
with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite,  quartz, 
epidote,  pyrite,  chalcopyrite,  chlorite. 

3£    G.  2.2  HETTLANDITE  (a  zeolite),  H4(Ca,Na2)Al2(SiO3)6-3H2O. 

4  Struct. — Tabular  monoclinic  crystals,  often  look  orthorhombic;  diamond- 
shaped,  striated;  foliated,  globular,  granular.  Cleavage  prominent,  one 
direction  (010);  brittle;  fracture  uneven. 

Color  white,  grayish,  red,  brown.  Streak  white.  Luster  vitreous;  pearly 
Transparent  to  translucent.  (See  p.  234.) 

Occurrence  and  associations  as  for  stilbite,  above. 

3i    G.  3.0-3.1     MARGAKITE  (Brittle  Mica),  H2CaAl4Si2Oi2;  some  Fe,  Na,  K. 
4|        Struct. — Micaceous,  scaly,  granular;   six-sided  scales,  plates  (monoclinic). 
Cleavage  perfect,  one  direction  (001);   flakes  rather  brittle;   not  elastic. 

Color  pink,  grayish,  white,  yellowish.  Streak  white.  Luster  pearly 
on  cleavage;  vitreous.  Translucent.  (See  pp.  236,  256.) 

Coating  or  associated  with  corundum;  also  chlorite,  spinel,  emery,  diaspora. 


SEC.  13]  PHYSICAL  TABLES  79 


4|     G.  2.3-2.4    APOPHYLLITE,  (H,K)2Ca(SiO3)2-H2O;  a  little  F. 
5          Struct.  —  Square  tabular  or  cube-like  tetragonal  crystals;  lamellar,  granular, 
compact.     Cleavage  perfect,  one  direction  (001);  brittle;  fracture  uneven. 

Color  white,  greenish,  yellowish,  reddish.  Streak  white.  Luster  vitreous; 
pearly  on  cleavage.  Transparent  to  nearly  opaque.  (See  p.  234.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite, 
quartz,  epidote,  pyrite,  chalcopyrite,  chlorite. 

5  G.  3.3-3.5    HYPERSTHENE  (a  pyroxene),  (Fe,Mg)SiO3;  sometimes  Al. 

6  Struct.  —  Foliated,     cleavable,     granular;      orthorhombic     crystals    rare. 
Cleavage  perfect,  one  direction  (010),  less  distinct,  two  directions  (110)  at 
46°,  88°,  92°,  and  134°;  brittle;  fracture  uneven. 

Color  grayish,  greenish,  and  brownish  black  to  bronze.  Streak  brownish 
gray,  grayish  white.  Luster  metalloidal  bronzy,  pearly.  Opaque  to  translu- 
cent. (See  pp.  222,  258.) 

In  basic  igneous  rocks  with  plagioclase  feldspars,  olivine,  amphibole, 
pyroxene,  magnetite,  titanite;  seldom  with  quartz. 

6      G.  3.2-3.4    ZOISITE,  Ca2Al3(OH)(Si04)3;  often  some  Fe. 
6|        Struct.  —  Columnar,   bladed,   fibrous,    compact;    prismatic  orthorhombic 
crystals  striated  lengthwise,  without  terminations.     Cleavage  conspicuous, 
one  direction  lengthwise  (010)  ;  brittle;  fracture  uneven. 

Color  gray,  yellowish  brown,  greenish;   also  red  (thulite).     Streak  white. 
Luster  vitreous;  pearly  on  cleavage.     Transparent  to  opaque.     (See  p.  246.) 
In   crystalline   schists  with  hornblende,   vesuvianite,    cyanite,   epidote, 
garnet,  feldspars,  quartz. 

6  G.  3.2-3.5    EPIDOTE  (Pistadte),  Ca«(Al,Fe)i(OH)(SiO4)i. 

7  Struct.  —  Long   monoclinic   crystals   striated  lengthwise,    commonly  ter- 
minated by  two  sloping  faces;  columnar,  divergent  acicular,  granular.    Cleav- 
age distinct,  one  direction  lengthwise  (001);   brittle;   fracture  uneven. 

Color  yellowish  green  to  brown  and  black,  gray,  yellow,  red.  Streak 
white  to  grayish.  Luster  vitreous.  Transparent  to  opaque.  (See  pp.  222, 
246.) 

In  gneiss,  schists,  crystalline  limestone,  greenstone;  with  garnet,  magnetite, 
chlorite,  native  copper,  zeolites. 

6  G.  3.2-3.3    SILLIMANITE  (Fibrolite),  Al2SiO6,  or  Al(AlO)SiO4. 

7  Struct.  —  Fibrous,    columnar,    radiating;     slender   orthorhombic    crystals 
without  terminations.     Cleavage   one  direction  lengthwise   (010);    brittle; 
fracture  splintery,  uneven. 

Color  grayish  white,  hair-brown,  greenish.  Streak  white.  Luster  vitre- 
ous, silky.  Transparent  to  translucent.  (See  p.  260.) 

In  gneiss;  in  contacts  of  aluminous  rocks,  with  andalusite,  cordierite, 
garnets,  corundum. 

6  G.  3.3-3.5    DIASPORE,  A1O-OH;  Al  45%;  sometimes  Fe. 

7  Struct.  —  Scaly,    bladed,    fibrous;     columnar    and   tabular   orthorhombic 
crystals  rare.     Cleavage  distinct,  one  direction  (010);  brittle;  fracture  con- 
choidal. 


80  DETERMINATIVE  MINERALOGY  [SECS.  13,  14 

H. 

Color  white,   grayish,    greenish,   hair-brown,   yellow,   colorless.      Streak 
white.     Luster  vitreous,  pearly.     Transparent  to  opaque.     (See  p.  260.) 
With  corundum,  emery,  dolomite,  margarite,  chlorite,  magnetite. 

6  G.  3.3-3.4    AXINITE,  HCa3Al2B(SiO4)4;  sometimes  Mn,  Fe,  Mg. 

7  Struct. — Tabular   wedge-shaped   triclinic    crystals    (Fig.    45);     lamellar, 
granular.     Cleavage  distinct,  one  direction  (010) ;  brittle;  fracture  con choidal. 

Color  clove-brown,  yellow,  greenish,  grayish  blue,  gray.      Streak  white. 
Luster  vitreous.     Transparent  to  translucent.     (See  p.  242.) 
In  veins  with  quartz,  feldspars,  hornblende,  chlorite. 

7  G.  2.6-2.7     CORDIERITE  (lolite,  Dichroite,  Water  Sapphire), 
7|  (Mg,Fe)4Al8(OH)2(Si207)5. 

Struct. — Short  six-  or  twelve-sided  orthorhombic  (pseudohexagonal)  crys- 
tals; granular,  sompact,  disseminated.  Cleavage  one  direction  lengthwise 
(010);  parting  cometimes  conspicuous  crosswise  (001);  brittle;  fracture 
uneven,  conchoidal. 

Color  light  to  dark  smoky  blue,  gray,  violet,  yellow.  Resembles  blue 
quartz;  often  altering  to  dull  green  chlorite;  transparent  varieties  show 
marked  differences  in  color  in  different  directions.  Streak  white.  Luster 
vitreous,  dull.  Transparent  to  translucent.  (See  pp.  244,  260.) 

In  schists,  gneiss,  sometimes  in  granite;  with  quartz,  feldspars,  hornblende, 
tourmaline,  andalusite,  sillimanite,  garnet. 

8  G.  3.4-3.6    TOPAZ,  Al2(F,OH)2SiO4. 

Struct. — Prismatic  orthorhombic  crystals  striated  lengthwise;  granular, 
pebbles,  compact.  Cleavage  perfect,  one  direction  crosswise  (001);  brittle; 
fracture  conchoidal,  uneven. 

Color  white,  colorless,  yellow,  pink,  bluish,  greenish.  Streak  white. 
Luster  vitreous.  Transparent  to  opaque.  (See  p.  260.) 

Veins  in  pegmatite,  rhyolite,  granite;  contacts;  placers;  with  tourmaline, 
cassiterite,  apatite,  fluorite,  beryl,  garnet. 


SECTION  14 

Streak  chalk- white,  colorless,  or  pale  colored;    mineral  yellow, 
red,  or  brown;  distinct  cleavage  two  directions. 

3|     G.  3.7  STRONTIANITE  (Strontian  Spar),  SrCO3;  SrO70.1%;  some- 

4  times  Ca. 

Struct. — Chisel-  or  spear-shaped  orthorhombic  crystals,  pseudohexagonal 
prisms;  columnar,  acicular,  fibrous,  divergent;  granular,  compact.     Cleavage 
•  distinct,  two  directions  at  63°  and  117°  (110);  brittle;  fracture  uneven. 

Color  white,  colorless,  grayish,  greenish,  yellowish.     Streak  white.    Luster 
vitreous,  greasy.     Transparent  to  translucent.     (See  p.  246.) 

In  ore  deposits  with  galena,   barite,   calcite,   celestite,   fluorite,   pyrite; 
veins  in  limestone,  chalk,  marl. 


SEC.  14]  PHYSICAL  TABLES  81 

H. 

4      G.  2.2  Phillipsite  (a  zeolite),  (Ca,K2)Al2(SiO3)4-5H2O;   often  Na. 

4|  Struct. — Monoclinic  penetration  twins,  often  like  orthorhombic  or  tetrago- 
nal; radial  tufts  or  spheres.  Cleavage  two  directions  at  90°  (010)  (001); 
brittle;  fracture  uneven. 

Color  white,  reddish.  Streak  white.  Luster  vitreous.  Translucent 
to  opaque.  (See  p.  232.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite, 
quartz,  epidote,  pyrite,  chalcopyrite,  chlorite. 

4f    G.  2.4-2.5    HARMOTOME  (azeoh'te),  H2BaAl2(SiO3)5-4H2O;  someNaandK. 

Struct. — Penetration  twins,  etc.  (monoclinic),  like  phillipsite  above,  with 
cleavage,  fracture,  etc.,  the  same. 

Color  white,  grayish,  yellow,  red  brown.  Streak  white.  Luster  vitreous. 
Translucent.  (See  pp.  232,  244.) 

Occurrence  and  associations  as  for  phillipsite,  above. 

4  G.  4.4-4.6    XENOTIME,  YPO4;  also  Er,  Ce,  Th,  etc. 

5  Struct. — Tetragonal  crystals  (prism,  pyramid);    compact,  disseminated, 
rolled  grains.     Cleavage  distinct,  two  directions  at  90°  (110);   brittle;   frac- 
ture uneven,  splintery. 

Color  yellow,  brown,  red,  pale  gray.  Streak  pale  brown,  yellowish, 
reddish.  Luster  greasy,  vitreous.  Translucent  to  opaque.  (See  p.  256.) 

Like  zircon  but  softer.  In  pegmatite  and  granitic  rocks  with  zircon, 
rutile;  in  sands. 

4^  G.  3.4-3.5  CALAMINE  (Electric  Calamine,  Hemimorphite),  (ZnOH)2SiO3; 
5  Zn  54.2%. 

Struct. — Tabular  orthorhombic-hemimorphic  crystals,  commonly  diver- 
gent cockscomb  groups;  mammillary,  stalactitic,  granular.  Cleavage  two 
directions  lengthwise  at  76°  and  104°  (110);  brittle;  fracture  uneven,  con- 
choidal. 

Color  white,  colorless,  yellowish,  brownish,  greenish,  bluish.  Streak 
white.  Luster  vitreous,  adamantine,  dull.  Transparent  to  translucent. 
(See  p.  252.) 

In  oxidized  zinc  ores,  usually  in  limestone  or  clay,  with  smithsonite,  ceru- 
site,  anglesite,  galena,  sphalerite,  calcite,  limonite. 


4|    G.  2.8-2.9    WOLLASTONITE  (a  pyroxene),  (Tabular  Spar),  CaSiO3. 
5          Struct. — Granular,  fibrous,  compact,  cleavable;   tabular  monoclinic  crys- 
tals.    Cleavage  distinct,  two  directions  at  84J°  and  95^°  (100)  (001);  brittle; 
fracture  uneven. 

Color  white,  grayish,  yellowish,  reddish,  brownish.     Streak  white.    Luster 
vitreous,  silky;  pearly  on  cleavage.     Translucent  to  opaque.     (See  p.  234.) 

In   limestone    contacts   with   pyroxene,    tremolite,    garnet,    vesuvianite, 
epidote,  graphite. 


82  DETERMINATIVE  MINERALOGY  [SEC.  14 

H. 

5      G.  2.2-2.3    NATROLITE  (Needle  Zeolite,}  Na2Al(AlO)(SiO3)3-2H2O. 

Struct. — Slender  orthorhombic  (pseudotetragonal)  crystals;  fibrous, 
radial,  granular,  compact.  Cleavage  two  directions  lengthwise  at  88°  and 
91°  (110);  brittle;  fracture  uneven. 

Color  white,  colorless,  grayish,  reddish,  yellowish.  Streak  white.  Luster 
vitreous,  silky.  Transparent  to  translucent.  (See  p.  230.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  metalliferous  veins; 
with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite,  quartz, 
epidote,  pyrite,  chalcopyrite,  chlorite. 

5      G.  3.4-3.6    TITANITE  (Spheric),  CaSiTiO6;  commonly  a  little  Fe. 

5|  Struct. — Tabular  or  wedge-shaped  monoclinic  crystals;  lamellar,  compact. 
Cleavage  distinct,  two  directions  at  66£°  and  113^°  (110);  parting  often  dis- 
tinct four  directions  at  54°  and  126°  (221);  brittle;  fracture  conchoidal. 

Color  brown  to  black,  yellow,  gray,  green;  rarely  rose-red.  Streak  white. 
Luster  vitreous,  resinous,  adamantine.  Transparent  to  opaque.  (See  pp. 
234,  246.) 

Accessory  in  many  igneous  rocks;  in  gneiss,  chlorite  schist,  crystalline 
limestone;  with  chlorite,  iron  oxides,  pyroxene,  amphibole,  zircon,  apatite, 
feldspars,  quartz,  rutile. 

5  G.  2.9-3.4    HORNBLENDE     (an    amphibole),    Ca(Mg,Fe)3(SiO3)4,    with 

6  A12O3  up  to  15  or  20%,  also  ferric  iron,  alkalies  (Na,  K), 
and  often  H  and  F. 

Struct. — Granular,  columnar,  fibrous,  radiated;  long  prismatic  mono- 
clinic  crystals,  often  rhombohedron-like  terminations;  prism  angle  124°; 
some  prisms  short,  six  sided.  Cleavage  perfect,  two  directions  lengthwise 
at  56°  and  124°  (110);  brittle;  fracture  uneven,  splintery. 

Color  green,  black,  brown,  gray.  Streak  brown,  green,  yellow,  gray, 
white.  Luster  submetallic,  vitreous,  pearly,  silky.  Translucent  to  opaque. 
(See  pp.  222,  238.) 

Common  in  igneous  and  metamorphic  rocks  with  feldspars,  pyroxenes, 
chlorite,  quartz,  calcite. 

5  G.  2.9-3.1    TREMOLITE  (Grammatite,  an  amphibole),  CaMg3(Si03)4. 

6  Struct. — Bladed,  columnar,  fibrous,  compact;   bladed  monoclinic  crystals 
without  terminations;   prism  angle  124°.     Cleavage  conspicuous,  two  direc- 
tions lengthwise  at  56°  and  124°  (110);  brittle;  small  fibers  flexible;  fracture 
uneven.     Nephrite  or  jade,  in  part  tremolite,  is  dense,  compact,  tough. 

Color  white  to  dark  gray,  yellowish,  colorless.  Streak  white.  Luster 
vitreous,  silky,  pearly.  Transparent  to  opaque.  (See  p.  238.) 

In  limestone,  dolomite,  schist;  common  at  contacts;  with  pyroxene, 
garnet,  vesuvianite,  epidote,  wollastonite. 

5  G.  3.0-3.2     Anthophyllite    (an    amphibole),     (Mg,Fe)Si03;    sometimes  Al 

6  (Gedrite). 

Struct. — Lamellar,  columnar,  fibrous;  prismatic  orthorhombic  crystals 
rare.  Cleavage  two  directions  lengthwise  at  54^°  and  125£°  (110);  brittle; 
fracture  splintery;  small  fibers  flexible  (asbestos). 


SEC.  14]  PHYSICAL  TABLES  83 

H. 

Color  gray,  clove-brown,  greenish  to  emerald.  Streak  white.  Luster 
vitreous,  pearly,  silky,  sometimes  metalloidal.  Translucent  to  opaque. 
(See  pp.  222,  238,  258.) 

In  schists  with  talc,  hornblende,  chlorite,  mica. 

5  G.  3.2-3.6    PYROXENE,     Ca(Mg,Fe)(SiO3)2,    ranging     from     Diopside, 

6  CaMg(Si03)2,  to    Hedenhergite,  CaFe(SiO3)2;    often  some 
Al,  Mn,  and  Na. 

AUGITE  (a  pyroxene),  like  common  pyroxene  above,  with 
A12O3  up  to  15  or  20%;  sometimes  alkali  metals,  Na  and  K. 

Struct. — Granular,  columnar,  rarely  fibrous;  lamellar  (diallage) ;  thick 
monoclinic  prisms  four-  or  eight-sided  (Figs.  40,  41).  Cleavage  two  directions 
lengthwise  at  87°  and  93°  (110),  sometimes  distinct;  parting  crosswise  (001), 
often  prominent;  diallage  has  fine  lamellar  parting  one  direction  lengthwise 
(100);  brittle;  fracture  uneven. 

Color  bright  to  dark  green,  grayish  green,  black,  brown.  Streak  greenish, 
brownish,  grayish  to  white.  Luster  vitreous,  submetallic,  dull.  Transparent 
to  opaque.  (See  pp.  220,  222,  240.) 

Common  in  basic  igneous  rocks;  in  crystalline  limestones  with  garnet, 
chlorite,  amphibole,  wollastonite,  magnetite,  pyrite. 

5  G.  3.1-3.3    ENSTATITE  (a  pyroxene),  (Mg,Fe)SiO3;  FeO  up  to  12%. 

6  Struct. — Lamellar,  columnar,  fibrous,  compact;    prismatic  orthorhombic 
crystals  rare.     Cleavage  distinct,  two  directions  at  88°  and  92°  (110) ;  parting 
one  direction  (010),  bisecting  cleavage  angle;  brittle;  fracture  uneven. 

Color  grayish  white,  yellowish,  greenish,  to  olive-green  and  brown.  Streak 
white.  Luster  vitreous,  pearly;  submetallic,  bronzy  (bronzite).  Translucent 
to  opaque.  (See  pp.  240,  258.) 

In  basic  igneous  rocks  (gabbro,  peridotite)  and  serpentine. 

5|    G.  4.0-4.1     Tephroite,  Mn2SiO4;  commonly  also  Mg  and  a  little  Fe. 
6          Struct. — Cleavable,    granular,    compact;     orthorhombic     crystals    rare. 
Cleavage  distinct,  two  directions  at  90°;  brittle;  fracture  conchoidal,  uneven. 
Color  ash-gray,  flesh-red,  brown.     Streak  pale  gray.    Luster  vitreous, 
greasy.     Translucent  to  opaque.     (See  p.  230.) 

In  crystalline  limestone  with  zincite,  willemite,  franklinite,  rhodonite 
(Franklin,  N.  J.);  with  other  manganese  minerals. 

Si     G.  3.4-3.7    RHODONITE,  MnSiO3;   often  Ca,  Fe;    sometimes  Zn  (Fow- 
6£  lerite). 

Struct. — Granular,  cleavable,  compact;  triclinic  crystals,  tabular,,  com- 
monly rough,  with  rounded  edges.  Cleavage  distinct,  two  directions  at  92^° 
and  87^°  (110);  brittle,  tough  when  compact;  fracture  conchoidal,  uneven. 
Color  brownish  red,  flesh-red,  pink;  sometimes  yellowish  or  greenish; 
may  tarnish  brown  or  black  on  exposure.  Streak  white.  Luster  vitreous. 
Transparent  to  opaque.  (See  p.  240.) 

In  veins;  in  crystalline  limestone  with  willemite,  franklinite,  zincite. 


84  DETERMINATIVE  MINERALOGY  [SEC.  14 

H. 

6      G.  3.0-3.1    AMBLYGONITE,  Li(AlF)PO4;  Li2O  10.1%;  sometimes  Na,  OH. 

Struct. — Cleavable,  compact,  columnar;  triclinic  crystals  rare.  Cleavage 
conspicuous,  one  direction  (001),  less  distinct  in  another  direction  at  83°  and 
97°  to  this  (100);  brittle;  fracture  uneven. 

Color  white,  pale  gray,  green,  blue,  yellow,  brown.  Streak  white.  Luster 
vitreous;  pearly  on  (001).  Translucent  to  opaque.  (See  p.  242.) 

Resembles  feldspars,  but  heavier.  Rare  in  pegmatite  with  tourmaline, 
lepidolite,  apatite,  topaz. 

6  G.  2.5-2.6  ORTHOCLASE  (Potash  Feldspar),  KAlSi3O8;  K2Q  16.9%; 
6|  often  Na 

Struct. — Cleavable,  granular,  disseminated  grains;  prismatic  and  tabular 
monoclinic  crystals  and  twins  (Figs.  42  to  44).  Cleavage  distinct,  two  direc- 
tions at  90°  (010)  (001);  brittle;  fracture  conchoidal,  uneven. 

Color  white,  red,  gray,  green,  colorless.  Streak  white.  Luster  vitreous; 
often  pearly  on  cleavage.  Transparent  to  opaque.  (See  p.  238.) 

In  many  igneous  and  metamorphic  rocks;  in  veins  and  contacts;  with 
quartz,  other  feldspars,  mica,  hornblende,  pyroxene;  in  pegmatite  with 
beryl,  topaz,  tourmaline.  For  description  of  varieties,  see  p.  37. 

6  G.  2.6-2.8  PLAGIOCLASE  (Soda-lime  or  Lime-soda  Feldspar),  ranging 
6^  from  NaAlSi3O8  (ab)  to  CaAl2Si2O8  (an);  generally  also 

some  K. 

Struct. — Lamellar,  granular,  disseminated;  small  triclinic  crystals  (Fig. 
46).  Cleavage  distinct,  two  directions  at  86°-86£°  and  94°-93£°  (001)  (010); 
often  striations  on  one  cleavage;  cleavage  often  curved;  brittle;  fracture 
uneven. 

Color  white,  colorless,  gray,  green,  bluish,  reddish;  sometimes  play  of 
colors — blue,  green,  yellow,  red.  Streak  white.  Luster  vitreous;  often 
pearly  on  cleavage.  Transparent  to  opaque,  sometimes  opalescent  (moon- 
stone), or  with  bright  reddish  or  yellowish  reflections  from  included  scales 
(aventurine  feldspar,  or  sunstone).  (See  p.  238.)  For  varieties,  see  p.  37. 

In  igneous  rocks,  gneisses,  schists,  with  other  feldspars,  quartz,  mica, 
chlorite,  zeolites;  sometimes  in  veins. 

6      G.  3.5-3.6     Aegirite  (Aegirine,  Acmite;  a  pyroxene),  NaFe'"(SiO3)2. 
65        Struct. — Long   prismatic    monoclinic    crystals   with   terminations   blunt 
(aegirite)  or  sharp  (acmite);   acicular,  fibrous.     Cleavage  distinct,  two  direc- 
tions at  87°  and  93°  (110);  brittle;  fracture  uneven. 

Color  greenish  black  to  reddish  and  brownish  black;  acmite  often  green 
interior,  brown  exterior.  Streak  pale  yellowish  gray.  Luster  vitreous,  resin- 
ous. Translucent  to  opaque.  (See  pp.  222,  240.) 

In  igneous  rocks  rich  in  soda  and  iron — aegirite  granite,  nephelite  syenite, 
phonolite,  pegmatite. 

6  G.  3.1-3.2    SPODUMENE  (a  pyroxene),  LiAl(SiO3)2;  Li2O  8.4%;  some  Na. 

7  Struct. — Cleavable,    columnar,    compact;    rough   prismatic   or   flattened 
monoclinic  crystals,  striated  lengthwise.     Cleavage  conspicuous,  two  direc- 
tions lengthwise  at  87°  and  93°  (110) ;  parting  one  direction  sometimes  promi- 
nent, bisecting  larger  cleavage  angle  (100);  brittle;  fracture  uneven;  splintery. 


SECS.  14,  15]  PHYSICAL  TABLES  85 

H. 

Color  white,  gray,  yellowish;  emerald-green  (hiddenite);  pink  to  purple 
(kunzite).  Streak. white.  Luster  vitreous,  pearly.  Transparent  to  opaque. 
(See  p.  240,  242.) 

In  pegmatites  with  tourmaline,  lepidolite,  beryl,  amblygonite,  cassiterite. 

6|    G.  3.2-3.6    OLIVINE   (Chrysolite,   Peridot],    (Mg,Fe)2Si04,   ranging  from 
7  For  sterile,  Mg2SiO4,  to  Fayalite,  Fe2SiO4;  sometimes  a  little 

Ni,  Sn,  Ti. 

Struct. — Granular,  disseminated;  prismatic  or  tabular  orthorhombic 
crystals  (Fig.  36)  rare.  Cleavage  indistinct,  two  directions  at  90°  (100)  (010) ; 
brittle;  fracture  conchoidal,  uneven. 

Color  yellowish  green,  yellowish  brown,  reddish.  Streak  white,  yellowish 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  p.  252.) 

In  basic  igneous  rocks  (gabbro,  basalt,  peridotite)  with  augite,  chromite, 
corundum,  spinel,  pyrope;  rarely  in  crystalline  dolomite. 

6£     G.  3.1-3.2    ANDALUSITE  (Chiastolite,  Made},  Al2Si05,  or  Al(A10)SiO4. 
7£        Struct. — Columnar,  granular,  disseminated;    rough  orthorhombic  prisms, 
nearly  square.     Cleavage  distinct,  two  directions  at  89°  and  91°  (110) ;  brittle; 
fracture  uneven. 

Color  white,  pink,  reddish  brown,  olive-green;  sometimes  black  and  white 
cross  or  checkered  pattern  on  cross-fracture  (chiastolite,  or  made);  Streak 
white.  Luster  vitreous,  dull.  Translucent  to  opaque.  (See  p.  260.) 

In  slate,  schists,  and  gneiss,  with  sillimanite,  garnet,  biotite,  tourmaline, 
cordierite. 

8|     G.  3.5-3.8    CHRYSOBERYL  (Cymophane),  G1A12O4. 

Struct. — Tabular  orthorhombic  crystals,  heart-shaped  or  pseudohexagonal 
twins,  disseminated  plates.  Cleavage  two  directions  at  60°  and  120°  (Oil); 
brittle;  fracture  uneven,  conchoidal. 

Color  yellowish  green,  deep  green,  greenish  white,  greenish  brown,  yellow. 
Streak  white.  Luster  vitreous,  greasy.  Transparent  to  translucent.  Alex- 
andrite, the  deep  green  variety,  is  red  by  gas  or  lamp  light;  cat's  eye  is  yel- 
lowish green,  opalescent.  (See  p.  260.) 

In  granite,  gneiss,  mica  schist,  placers;  with  beryl,  garnet,  tourmaline, 
sillimanite, 


SECTION  16 

Streak  chalk-white,  colorless,  or  pale  colored;    mineral  yellow, 
red,  or  brown;   distinct  cleavage  three  or  more  directions. 

11     G.  2.3-2.4     GYPSUM  (Selenite,  Alabaster,  Satin  Spar),  CaSO4-2H20. 

2  Struct. — Granular,  foliated,  fibrous;  earthy  (gypsite);  diamond-shaped 
monoclinic  crystals  with  beveled  edges  (Figs.  38,  39).  Cleavage  perfect,  one 
direction  (010),  two  others  less  conspicuous  (111)  (100)  at  90°,  66°,  and  114°; 
brittle,  thin  flakes  flexible;  fracture  conchoidal,  splintery. 


86  DETERMINATIVE  MINERALOGY  [SEC.  15 

H. 

Color  white,  colorless,  gray,  yellow,  red.  Streak  white.  Luster  vitreous; 
pearly  on  (010);  silky.  Transparent  to  opaque.  (See. pp.  224,  226.) 

Beds  and  masses  with  limestone,  clay,  shale,  rock  salt;  near  volcanic 
vents;  with  anhydrite,  celestite,  sulphur,  calcite,  aragonite. 

2      G.  2.1-2.6    HALITE  (Common  Salt,  Rock  Salt),  NaCl;   Na  60.6%;   often 
2|  Ca  and  Mg. 

Struct. — Granular,  cleavable,  compact;  isometric  crystals  (cubes,  Fig.  5). 
Cleavage  distinct,  three  directions  at  90°  (100);  brittle;  fracture  conchoidal. 
Color  white,  colorless,  grayish,  reddish,  bluish.     Streak  white.    Luster 
vitreous.     Transparent  to  translucent.     Taste  salty.     (See  p.  224.) 

Beds  in  sedimentary  strata  with  gypsum,  anhydrite,  sylvite,  calcite,  clay, 
sand;  in  dry  lakes;  in  brines.  (Compare  Cryolite,  p.  95.) 

2  G.  1.9-2.0    SYLVITE,  KC1;  K  52.4%;  sometimes  Na. 

2%  Struct. — Granular,  compact;  isometric  crystals  (cubes,  Fig.  5).  Cleavage 
distinct,  three  directions  at  90°  (100);  brittle;  fracture  conchoidal. 

Color  white,  colorless,  grayish,  bluish,  reddish.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  Taste  salty,  bitter.  Becomes  damp 
in  moist  air.  (See  p.  224.) 

In  salt  deposits;  with  halite,  kainite,  carnallite. 

2£    G.  2.0-2.2    KAINITE,  KMgClSO4-3H2O;  K  18.9%. 

3  Struct. — Compact,  fine  granular;   rarely  tabular  or  prismatic  monoclinic 
crystals.     Cleavage  distinct,  three  directions  at  39?°,  101^°,  and  140£°  (100) 
(110),  brittle;  fracture  uneven. 

Color  white,  colorless,  reddish.     Streak  white.    Luster  vitreous.     Trans- 
parent to  translucent.     Taste  salty,  bitter,  astringent.     (See  p.  224.) 
In  beds  with  halite,  sylvite,  gypsum,  anhydrite. 

2£    G.  4.3-4.6    BARITE  (Baryles,  Heavy  Spar),  BaSO4;  sometimes  Ca  and  Sr. 
3|        Struct. — Tabular  and  prismatic  orthorhombic  crystals,  divergent  groups; 
compact,  lamellar,  fibrous.     Cleavage  distinct,  three  directions  at  78%°,  90°, 
and  101£°  (001)  (110);   brittle;   fracture  uneven. 

Color  white,  colorless,  light  shades  of  yellow,  brown,  red,  blue.  Streak 
white.  Luster  vitreous,  pearly.  Transparent  to  opaque.  (See  p.  226.) 

In  veins  with  galena,  sphalerite,  fluorite,  chalcopyrite;  in  limestones  and 
residual  clays  with  manganese  and  iron  oxides. 

3      G.  2.7  CALCITE  (Cole  Spar),  CaCO»;  often  Mg,  Fe,  Mn,  sometimes  Pb. 

Struct. — Hexagonal-rhombohedral  crystals,  prismatic,  scalenohedral, 
rhombohedral,  tabular,  or  acicular  in  habit  (Figs.  52  to  57).;  rarely  twins; 
cleavable,  granular,  stalactitic,  oolitic,  earthy.  Cleavage  perfect,  three  direc- 
tions at  75°  and  105°  (lOll);  brittle;  fracture  conchoidal.  seldom  observed. 

Color  white,  colorless,  pale  shades  of  gray,  yellow,  red,  green,  blue,  violet; 
brown  to  black  when  impure.  Streak  white.  Luster  vitreous,  dull.  Trans- 
parent to  opaque.  (See  p.  246.) 

Chief  constituent  of  limestone,  marble,  chalk,  calcareous  marl;  in  veins 
with  metallic  ores,  quartz,  pyrite,  zeolites.  (For  varieties  see  p.  40.) 


SEC.  15]  PHYSICAL  TABLES  87 

H. 

3      G.  6.1-6.4    ANGLESITE  (Lead  Vitriol)  PbSO4;  Pb  68.3%. 

Struct. — Orthorhombic  crystals;  granular,  compact.  Cleavage  three 
directions  at  76°,  90°,  and  104°  (001)  (110),  not  conspicuous;  brittle;  fracture 
conchoidal. 

Color  white,  colorless,  gray,  brown,  green.  Streak  white.  Luster  ada- 
mantine, vitreous.  Transparent  to  translucent.  (See  p.  214.) 

In  oxidized  parts  of  ore  deposits  with  lead,  zinc,  and  iron  minerals. 

3      G.  2.9-3.0    ANHYDRITE     (Anhydrous  Gypsum),  CaSO4. 
3|        Struct. — Granular,  compact,  fibrous,  cleavable;  rarely  orthorhombic  crys- 
tals.    Cleavage  distinct,  three  directions  at  90°  (001)  (100)  (010);    brittle; 
fracture  conchoidal. 

Color  white,  grayish,  bluish,  reddish,  to  brick-red.  Streak  white  to 
grayish.  Luster  vitreous;  pearly  on  (001).  Translucent  to  opaque.  (See 
p.  226.) 

In  limestones,  shales,  salt  deposits;  with  nalite,  gypsum,  calcite. 

3  G.  3.9-4.0    CELESTITE,  SrSO4;  sometimes  Ca  and  Ba. 

3£  Struct. — Tabular  or  prismatic  orthorhombic  crystals  (Fig.  37);  fibrous, 
cleavable,  rarely  granular.  Cleavage  distinct,  three  directions  at  76°.  90°, 
and  104°  (001)  (110);  brittle;  fracture  uneven. 

Color  white,  colorless,  bluish,  reddish.  Streak  white.  Luster  vitreous, 
pearly.  Transparent  to  translucent.  (See  p.  226.) 

In  limestones  and  shales  with  gypsum,  halite,  sulphur,  galena,  aragonite. 

3|    G.  2.8-2.9  DOLOMITE  CaMg(CO3)2;  sometimes  Fe  and  Mn  (much  Fe, 

4  Ankerite). 

Struct. — Granular,  cleavable,  compact;  hexagonal-rhombohedral  crystals, 
faces  often  curved  (pearl  spar).  Cleavage  perfect,  three  directions  at  74° 
and  106°  (lOll);  brittle;  fracture  conchoidal,  uneven. 

Color  white,  colorless,  gray,  red,  green,  brown,  black.  Streak  white. 
Luster  vitreous,  pearly.  Transparent  to  opaque.  (See  p.  246.) 

Extensive  strata  as  dolomitic  limestone  and  marble;  gangue  with  ores 
of  lead,  zinc,  etc.;  with  serpentine,  talc,  gypsum,  and  ordinary  limestones. 

3|  G.  3.8-3.9  SIDERITE  (Spathic  Iron,  ChalyUte,  Clay  Ironstone,  Black 
4  Band  Ore),  FeCO3;  Fe  48.3%;  sometimes  Mg,  Mn,  Ca. 

Struct. — Granular,  cleavable,  compact;  hexagonal-rhombohedral  crystals, 
curved  and  saddle-shaped  common.  Cleavage  perfect,  three  directions  at 
73°  and  107°  (lOll);  brittle;  fracture  uneven. 

Color  gray,  yellow,  brown,  black,  sometimes  white.  Streak  white,  pale 
yellow.  Luster  vitreous,  pearly,  dull.  Translucent  to  opaque.  (See  pp. 
218,  248.) 

In  veins  with  silver  minerals,  pyrite,  and  other  sulphides,  cryolite;  beds 
and  concretions  in  limestone,  shale,  coal. 

3|     G.  2.9-3.0    ARAGONITE  (Flos  Ferri),  CaCO3;  sometimes  Sr  and  Pb. 

4  Struct. — Chisel-  or  spear-shaped  orthorhombic  crystals,  pseudohexagonal 
prisms;  acicula'r,  columnar,  stalactitic,  coral-like.  Cleavage  three  directions 
at  64°,  90°,  and  116°  (110)  (010);  brittle;  fracture  conchoidal. 


88  DETERMINATIVE  MINERALOGY  [SEC.  13 

H. 

Color  white,  gray,  yellow,  pale  green,  violet.  Streak  white.  Luster 
vitreous,  resinous.  Transparent  to  translucent.  (See  p.  246.) 

In  gypsum  beds,  basalt,  serpentine,  beds  of  limonite  and  siderite;  with 
celestite,  sulphur,  metallic  sulphides,  zeolites;  constitutes  some  shells  (pearly 
layers  of  many)  and  coral. 

3|     G.  3.9-4.1     SPHALERITE  (Blende,  Zinc  Blende,  Jack,  Black  Jack,  .Rosin 

4  Jack),  ZnS;   Zn  67%;   may  be  replaced  by  Fe  up  to  18%. 

Struct. — Cleavable    masses,    granular,    compact,    botryoidal;     rounded 

isometric-tetrahedral  crystals.     Cleavage  pronounced,  six  directions  at  60°, 

90°,  and  120°  (110);  brittle;  fracture  conchoidal. 

Color  yellow,  brown,  red,  green,  black;  rarely  white  or  pale  gray  (cleio- 
phanc).  Streak  white,  light  to  dark  brown.  Luster  resinous,  adamantine, 
submetallic.  Transparent  to  opaque.  (See  pp.  200,  228,  250.) 

Ore  deposits  and  veins  with  galena,  pyrite,  chalcopyrite,  fiuorite,  barite; 
also  in  limestones. 

3£    G.  2.2-2.3    LAXTMONTITE  (a  zeolite),  HCa(AlO)2(Si03)4-2H2O. 

4          Struct. — Radial,  divergent,  columnar;   prismatic  monoclinic  crystals  with 

oblique  terminations.     Cleavage  three  directions  lengthwise  at  86°,  94°.  and 

137°  (110)  (010);  brittle,  friable;  fracture  uneven,  earthy. 

Color  white,  yellowish,  grayish,  reddish.     Streak  white.     Luster  vitreous, 

pearly.     Transparent  to  opaque.     Becomes  dull,  opaque,  and  powdery  on 

exposure.     (See  p.  230.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;    in  metalliferous 

veins;  with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite, 

quartz,  epidote.  pyrite,  chalcopyrite,  chlorite. 

3|  G.  3.4-3.6  RHODOCHROSITE  (Dialogite),  MnCO3;  Mn  47.8%;  some- 
4|  times  Fe,  Ca,  Mg. 

Struct. — Cleavable,  granular,  compact,  botryoidal,  incrusting;  hexagonal- 
rhombohedral  crystals  rare,  commonly  with  curved  faces.  Cleavage  con- 
spicuous, three  directions  at  73°  and  107°  (1011) ;  brittle;  fracture  uneven. 

Color  reddish  white,  rose-red,  dark  red,  brown;  brown  to  black  on  ex- 
posure. Streak  white.  Luster  vitreous,  pearly.  Transparent  to  translucent. 
(See  p.  248.) 

In  veins  with  other  manganese  minerals,  ores  of  silver,  lead,  and  copper; 
pyrite. 

3|  G.  3.0-3.1  MAGNESITE,  MgCO3;  sometimes  much  Fe  (Breunnerite\\ 
4}  also  Mn. 

Struct. — Compact  like  unglazed  porcelain,  granular,  cleavable;  rarely 
hexagonal-rhombohedral  crystals.  Cleavage  conspicuous,  three  directions 
at  72£°  and  107|°  (lOll);  tough  to  brittle;  fracture  conchoidal. 

Color  white,  yellowish,  grayish,  brown.  Streak  white.  Luster  vitreous, 
dull.  Transparent  to  opaque.  (See  p.  248.) 

Forming  extensive  beds;  disseminated  in  talc  and  chlorite  schists;  veins 
in  serpentine,  dolomite,  limestone;  with  gypsum. 


SEC.  15]  PHYSICAL  TABLES  89 

H. 

4  G.  3.0-3.2  FLUORITE  (Fluor  Spar,  Blue  John),  CaF2;  F48.9%;  some- 
times Cl. 

Struct. — Isometric  crystals  (cubes,  Fig.  5),  penetration  twins;  cleavable 
masses,  granular,  columnar.  Cleavage  perfect,  four  directions  at  70|?  and 
109|°  (111);  brittle;  fracture  uneven. 

Color  violet,  blue,  green,  yellow,  colorless,  brown.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  (See  p.  226.) 

Common  in  veins  and  contacts  with  galena,  sphalerite,  calcite,  barite, 
cassiterite,  apatite,  topaz,  lepidolite;  in  limestones;  rare  in  igneous  rocks. 

4  G.  2.0-2.2    CHABAZITE     (a  zeolite),  CaAl2(SiO3)4-6H2O;    often  K,  Na, 

5  Ba,  Sr. 

Struct. — Hexagonal-rhombohedral  crystals  (cube-like  rhombohedrons), 
also  modified  forms,  twins;  compact.  Cleavage  distinct,  three  directions 
at  85°  and  95°  (lOll);  brittle;  fracture  uneven. 

Color  white,  yellow,  flesh-red.  Streak  white.  Luster  vitreous.  Trans- 
parent to  translucent.  (See  p.  234.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite, 
quartz,  epidote,  pyrite,  chalcopyrite,  chlorite. 

4|  G.  5.9-6.2  SCHEELITE,  CaWO4;  WO380.6%;  some  Mo;  sometimes  Cu 
5  (Cuproscheelite) . 

Struct. — Small  pyramidal  tetragonal  crystals  resembling  octahedrons, 
sometimes  tabular;  incrusting,  granular,  compact.  Cleavage  distinct,  four 
directions  at  80°,  110°,  and  130£°  (111);  brittle;  fracture  conchoidal,  uneven. 

Color  white,  yellow,  brownish,  greenish,  reddish.  Streak  white  to  yellow- 
ish. Luster  greasy,  adamantine.  Transparent  to  translucent.  (See  pp.  234, 
254,  258.) 

In  veins  and  contacts  with  quartz,  cassiterite,  topaz,  fluorite,  apatite, 
molybdenite. 

5  G.  4.3-4.5  SMITHSONITE  (Dry  Bone;  Calamine,  in  England),  ZnCO3; 
Zn  52.1%. 

Struct. — Mammillary,  stalactitic,  incrusting,  cellular  (dry  bone);  rarely 
small  hexagonal-rhombohedral  crystals  with  cleavage  distinct,  three  direc- 
tions at  72°  and  108°  (lOll);  brittle;  fracture  uneven,  splintery. 

Color  white,  grayish,  colorless,  greenish,  blue,  pink,  brown.  Streak 
white.  Luster  vitreous,  adamantine,  pearly,  dull.  Transparent  to  opaque, 
(See  p.  248.) 

In  oxidized  zinc  ores,  usually  in  limestone  or  clay,  with  calamine,  cerusite, 
anglesite,  galena,  sphalerite,  calcite,  limonite. 

5  G.  3.2-3.6    PYROXENE,     Ca(Mg,Fe)(SiO3)2,     ranging     from     Diopside, 

6  CaMg(SiO3)2,   to    Hedenbergite,  CaFe(SiO3)2;    often  some 
Al,  Mn,  and  Na. 

AUGITE   (a  pyroxene),   like  common  pyroxene  above,  with 

A12O3  up  to  15  or  20%;  sometimes  alkali  metals,  Na  and  K. 

Struct. — Granular,   columnar,  rarely  fibrous;    lamellar   (diallage);    thick 


90  DETERMINATIVE  MINERALOGY  [SBC.  lo 


monoclinic  prisms  four-  or  eight-sided  (Figs.  40,  41).  Cleavage  two  directions 
lengthwise  at  87°  and  93°  (110),  sometimes  distinct;  parting  crosswise  (001), 
often  prominent;  diallage  has  fine  lamellar  parting  one  direction  lengthwise 
(100);  brittle;  fracture  uneven. 

Color  bright  to  dark  green,  grayish  green,  black,  brown.  Streak  greenish, 
brownish,  grayish  to  white.  Luster  vitreous,  submetallic,  dull.  Transparent 
to  opaque.  (See  pp.  220,  222,  240.) 

Common  in  basic  igneous  rocks;  in  crystalline  limestones  with  garnet, 
chlorite,  amphibole,  wollastonite,  magnetite,  pyrite. 


5  G.  3.1-3.3    ENSTATITE  (a  pyroxene),  (Mg,Fe)SiO3;  FeO  up  to  12%. 

6  Struct.  —  Lamellar,  columnar,  fibrous,  compact;    prismatic  orthorhombic 
crystals  rare.     Cleavage  distinct,  two  directions  at  88°  and  92°  (110);  parting 
one  direction  (010),  bisecting  cleavage  angle;  brittle;  fracture  uneven. 

Color  grayish  white,  yellowish,  greenish,  to  olive-green  and  brown.  Streak 
white.  Luster  vitreous,  pearly;  submetallic,  bronzy  (bronzite).  Translucent 
to  opaque.  (See  pp.  240,  258.) 

In  basic  igneous  rocks  (gabbro,  peridotite)  and  serpentine. 

5  G.  2.5-2.6    NEPHELITE  (Nephdine,  Elaeolite;  a  feldspathoid),  NaAlSKX; 

6  also  K2O  up  to  7%. 

Struct.  —  Compact,  disseminated,  grains;  small  hexagonal  crystals  rare. 
Cleavage  distinct,  three  directions  at  60°  and  120°  (10lO);  brittle;  fracture 
conchoidal,  uneven. 

Color  reddish,  brownish,  greenish,  gray,  white,  colorless.  Streak  white. 
Luster  greasy,  vitreous.  Transparent  to  opaque.  (See  p.  232.) 

In  lavas  and  granular  igneous  rocks  with  feldspars,  sodalite,  cancrinite, 
biotite,  zircon,  corundum;  not  with  quartz. 


5  G.  2.6-2.8    WERNERITE 

6  Struct.  —  Stout  prismatic  tetragonal  crystals;   compact,  fibrous,  granular. 
Cleavage  three  directions  lengthwise  at  45°  and  90°  (100)   (110),  not  con- 
spicuous; brittle;  fracture  conchoidal,  uneven. 

Color  white,  gray,  greenish,  bluish,  reddish.  Streak  white.  Luster  vitre- 
ous, greasy.  Translucent  to  opaque.  (See  pp.  234,  244.) 

In  crystalline  limestones  and  schists  with  pyroxenes,  amphiboles,  apatite, 
garnet,  biotite. 

5  G.  3.9-4.2    WILLEMITE,   Zn2SiO4;    Zn  58%;    may  contain  Mn  (Trooslite) 

6  .  some  Fe. 

Struct.  —  Compact  granular,  disseminated;  prismatic  hexagonal-rhombo- 
hedral  crystals  rare.  Cleavage  distinct,  three  directions  at  60°  and  120° 
(1120);  brittle;  fracture  conchoidal,  uneven. 

Color  yellow,  green,  red,  brown,  white.  Streak  white.  Luster  vitreous. 
Transparent  to  opaque.  (See  pp.  232,  252.) 

In  crystalline  limestone  with  franklinite,  zincite,  rhodonite. 


SEC.  15]  PHYSICAL  TABLES  91 

H. 

5  G.  3.3-3.5    HYPERSTHENE  (a  pyroxene),  (Fe,Mg)SiOs;  sometimes  Al. 

6  Struct. — Foliated,     cleavable,    granular;     orthorhombic    crystals    rare. 
Cleavage  perfect,  one  direction  (010),  less  distinct,  two  directions  (110)  at 
46°,  88°,  92°,  and  134°;  brittle;  fracture  uneven. 

Color  grayish,  greenish,  and  brownish  black  to  bronze.  Streak  brownish 
gray,  grayish  white.  Luster  metalloidal  bronzy,  pearly.  Opaque  to  translu- 
cent. (See  pp.  222,  258.) 

In  basic  igneous  rocks  with  plagioclase  feldspars,  olivine,  amphibole, 
pyroxene,  magnetite,  titanite;  seldom  with  quartz. 

5  G.  2.4-2.5    CANCRINITE    (a  feldspathoid),  H6Na6Ca(NaCO3)2Al8(Si04)9. 

6  Struct. — Compact,   lamellar,   columnar,   disseminated;    prismatic  hexag- 
onal crystals  rare.     Cleavage  distinct,  three  directions  at  60°  and  120°  (lOll); 
brittle;  fracture  uneven. 

Color  white,  gray,  yellow,  green,  blue,  reddish.  Streak  white.  Luster 
vitreous,  greasy,  pearly.  Transparent  to  translucent.  (See  p.  230.) 

In  granular  igneous  rocks  with  nephelite,  sodalite,  biotite,  feldspars, 
titanite;  not  with  quartz. 

51     G.  3.8-3.9    Octahedrite  (Anatase),  TiO2;   Ti  60%. 

6  Struct. — Tetragonal  crystals,  pyramidal,  tabular,  rarely  prismatic.  Cleav- 
age distinct,  five  directions  at  82°,  111°,  and  136£°  (111)  (001);  brittle;  frac- 
ture uneven. 

Color  brown,  dark  blue,  black.  Streak  white,  pale  gray.  Luster  adaman- 
tine, metallic.  Translucent  to  opaque.  (See  pp.  210,  262.) 

Minute  crystals  in  granular  igneous  rocks;  in  gneiss,  schists,  quartzite, 
limestone;  with  brookite,  rutile,  ilmenite,  biotite,  adularia,  titanite,  gold. 

5|     G.  4.0  Perovskite  (Perofskite),  CaTi03;  some  Fe. 

6  Struct. — Isometric  (or  pseudoisometric)  crystals,  commonly  cubes  (Fig.  5), 
often  highly  modified  and  striated;  reniform  aggregates,  rounded  grains. 
Cleavage  distinct,  three  directions  at  90°  (100);  brittle;  fracture  uneven. 

Color  pale  yellow  to  orange-yellow,  reddish  brown,  grayish  black.  Streak 
white,  grayish.  Luster  adamantine,  submetallic.  Transparent  to  opaque. 
(See  pp.  210,  258.) 

In  schists,  crystalline  limestone,  serpentine,  basic  igneous  rocks;  with 
chlorite,  magnetite,  garnet,  vesuvianite,  rutile,  ilmenite,  corundum. 

61    G.  3.4-4.3    GARNET,  R3"R2"'(Si04)3;    R"=Ca,  Mg,  Fe,  Mn,  Ti; 
7|  R'"  =  A1,  Fe,  Cr,  Ti. 

Struct. — Isometric  crystals  (dodecahedrons,  trapezohedrons,  Figs.  3,7,  8); 
granular,  lamellar,  compact,  disseminated,  sand.  Cleavage  none;  parting, 
sometimes  distinct,  six  directions  at  60°,  90°,  120°  (110);  brittle;  fracture  con- 
choidal,  uneven. 

Color  red,  brown,  black,   etc.      (see  varieties,  p.  101).     Streak  white. 
Luster  vitreous.     Transparent  to  opaque.     (See  p.  244.) 
For  varieties  and  occurrence,  see  p.  101. 


92  DETERMINATIVE  MINERALOGY  [SECS.  15,  16 


7£    G.  2.9-3.0    PHENACITE,  GUSiO4. 

8  Struct.  —  Hexagonal-rhombohedral  crystals,  prismatic,  lenticular.     Cleav- 
age indistinct,  three  directions  at  60°  and  120°  (1120);  brittle;  fracture  con- 
choidal. 

Color  colorless,  wine-yellow,  rose-red,  brown.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  (See  p.  264.) 

In  pegmatite  and  metamorphic  rocks  with  quartz,  topaz,  beryl,  microcline, 
chrysoberyl. 

9  G.  3.9-4.1    CORUNDUM     (Adamantine  Spar),  A1203. 

Struct.  —  Rough  hexagonal-rhombhedral  crystals,  prismatic,  pyramidal, 
tabular,  tapering  (barrel-shaped),  often  striated;  lamellar,  granular,  compact. 
Cleavage  none;  often  conspicuous  parting  three  directions  at  86°  and  94° 
(1011);  sometimes  transverse  parting  (0001);  brittle,  tough  when  compact; 
fracture  uneven,  conchoidal. 

Color  white,  gray,  brown  to  black;  deep  red  (ruby);  blue  (sapphire); 
black  from  admixture  of  magnetite,  hematite,  or  spinel  (emery).  Streak 
white.  Luster  vitreous,  adamantine.  Transparent  to  opaque.  (See  p.  260.) 

In  peridotite,  gneiss,  schist,  syenite,  crystalline  limestone;  with  olivine, 
chlorite,  serpentine,  magnetite,  spinel,  vermiculite;  cyanite,  diaspore,  muscc- 
vite. 

10  G.3.5          DIAMOND  (Carbon),  C. 

Struct.  —  Isometric  crystals  (octahedron,  hexoctahedron,  Figs.  1,  4) 
usually  with  curved  surfaces;  rounded  and  irregular  grains,  pebbles,  often 
with  radial  structure.  Cleavage  distinct,  four  directions  at  70|°  and  109^° 
(111);  brittle;  fracture  conchoidal. 

Color  white,  colorless,  pale  shades  of  yellow,  red,  orange,  green,  blue, 
brown;  occasionally  black.  Streak  white.  Luster  adamantine,  greasy. 
Transparent  to  opaque.  (See  p.  264.)  For  description  of  varieties,  see 
p.  45. 

In  peridotite  or  serpentine;  in  sands,  gravels  quartzite;  with  pyrope, 
magnetite,  chromite,  zircon,  gold. 

SECTION  16 

Streak  chalk-  white,  colorless,  or  pale  colored;    mineral  yellow, 
red,  or  brown;  no  distinct  cleavage. 

0  KAOLINITE,  BAUXITE,  CHALK,  TRIPOLITE,  GYPSITE. 

1  Powdery,  earthy,  or  clay-like  minerals,  which  may  be  colored  yellow, 
red,  or  brown  by  ferric  oxides,  although  white   when  pure.      (See  pp.  30, 
40,  46,  47.) 

0      G.  4.5    Molybdite  (Molybdic  Ocher),  Fe2(MoO4)3-7|H2O;   MoO3  59.4%. 

1£         Struct.  —  Earthy  powder,   crusts;    rarely  fibrous,  radiating,  or  hair-like 

orthorhombic   crystals.     Cleavage   distinct,   one   direction   crosswise    (001); 

brittle. 


SEC.  16]  PHYSICAL  TABLES  93 

H. 

Color  and  streak  straw-yellow,  yellowish  white.  Luster  dull,  silky.  Trans- 
lucent to  opaque.  (See  p.  228.) 

With  molybdenite,  of  which  it  is  an  alteration  product. 

1      G.  5.5-5.6    CERAEGYRITE  (Horn  Silver},  AgCl;  Ag  75.3%;  sometimes  Hg. 
1£        Struct.  —  Wax-like  crusts,  stalactitic,  dendritic;   isometric  (cubic)  crystals 
rare.     Cleavage  none;  highly  sectile;  fracture  conchoidal. 

Color  pearly  gray,  greenish,  colorless;  turns  violet,  brown  to  black  on 
exposure  to  light.  Streak  white,  grayish,  shiny.  Luster  waxy,  greasy,  resin- 
ous. Transparent  to  translucent.  (See  p.  216.) 

In  veins  with  other  silver  minerals,  calcite,  barite,  limonite. 

1      G.  5.3-5.8    EMBOLITE,  Ag(Cl,Br);  Ag  60-70%. 

1|        Struct.  —  Compact,    stalactitic,    concretionary;     isometric    crystals   rare. 
Cleavage  none;  sectile;  fracture  uneven. 

Color  yellow,  grayish  green,  yellowish  green,  becoming  darker  on  exposure. 
Streak  white.  Luster  resinous,  adamantine.  Transparent  to  translucent. 
(See  p.  216.) 

In  oxidized  parts  of  silver  veins  with  calcite,  barite,  limonite. 

1  G.  1.6  CAKNALLITE,  KMgCl3-6H2O;  KC1  26.8%. 

2  Struct.  —  Granular,   compact;    orthorhombic   (pseudohexagonal)   crystals 
rare.     Cleavage  indistinct;   brittle;  fracture  conchoidal. 

Color  white,  grayish,  brownish,  reddish.  Streak  white.  Luster  vitreous, 
greasy.  Transparent  to  translucent.  Bitter  taste;  absorbs  moisture  and 
liquefies  in  moist  air.  (See  p.  224.) 

With  halite,  kieserite,  sylvite,  boracite,  anhydrite. 

1  G.  0.9-1.0    OZOCERITE  (Mineral  Wax,  Native  Paraffin),  CnH2n+2- 

2  Struct.  —  Amorphous,  compact,  fibrous,  lamellar;  plastic;  may  be  sticky. 
Color  black,  brownish  black,  brownish  yellow,  leek-green.     Streak  yellow- 

ish brown,   pale  yellow.     Luster  waxy,   greasy,   submetallic.     Translucent, 
sometimes  greenish  opalescence.     Like  wax;  greasy  feel.     (See  p.  212.) 

Burns  with  bright  smoky  flame  and  odor  of  paraffin.  In  veins  in  sedi- 
mentary rocks. 

1  G.  6.4-6.5     Calomel  (Horn  Quicksilver),  Hg2Cl2;  Hg  84.9%. 

2  Struct.  —  Coatings;  small  tetragonal  crystals,  tabular,  pyramidal.     Cleav- 
age indistinct,  two  directions  at  90°  (100);  fracture  conchoidal;  sectile. 

Color  white,   gray,   yellowish,   brown.     Streak  white,   gray,   yellowish. 
Luster  adamantine.     Translucent  to  opaque.     (See  p.  212.) 
In  veins  with  cinnabar  and  mercury. 


1      G.  2.4-2.6    KAOLINITE  (Kaolin,  China  Clay,  Porcelain  Clay), 
2%        Struct.  —  Friable,   clay-like,   compact;    minute  scaly  monoclinic  crystals 
(pseudohexagonal  or  pseudorthorhombic)  rare;   brittle;   fracture  earthy. 

Color  white,  gray,  yellowish,  reddish.     Streak  white.'    Luster  dull,  pearly. 
Opaque  to  translucent.     Generally  plastic  when  moist.     (See  p.  256.) 

With  quartz,  feldspars;   largely  from  decomposition  of  latter;   chief  con- 
stituent of  most  clay.     For  varieties  see  p.  47.     (Compare  Bauxite,  p.  47.) 


94  DETERMINATIVE  MINERALOGY  [SEC.  16 

H. 

1  G.  2.1-2.2    TRIPOLITE  (Tripoli,  Infusorial  Earth,  Diatomite,  Diatomace- 
3  ous  Earth),  SKVwH^O;  the  composition  of  opal. 

Struct. — Amorphous,  porous,  earthy,  chalk-like;  particles  scratch  glass; 
harsh  feel;  not  plastic  when  wet. 

Color  white,  gray  yellowish.  Streak  white.  Luster  dull.  Opaque. 
(See  p.  54.) 

Associated  with  and  in  part  mingled  with  clay,  sand,  peat. 

1J     G.  2.2-2.3    SODA  NITER  (Chile  Saltpeter),  NaN03;  N2O6  63.5%. 

2  Struct. — Granular,  crusts,  efflorescences;   rarely  hexagonal-rhombohedral 
crystals,  like  calcite.     Cleavage  distinct,  three  directions  at  73^°  and  106^° 
(lOll);  brittle,  somewhat  sectile;  fracture  conchoidal. 

Color  white,  colorless,  grayish,  yellowish,  brownish.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  Taste  cool,  salty;  becomes  damp  in 
moist  air.  (See  p.  224.) 

Extensive  deposits  in  some  arid  districts  (Chile);  with  gypsum,  sand, 
clay,  guano. 

If    G.  2.0-2.1    SULPHUR  (Brimstone),  S;  traces  of  Te,  Se,  As. 
2£        Struct. — Granular,   fibrous,   compact,   earthy;    reniform,   stalactitic,   in- 
crusting;  orthorhombic  crystals,  pyramidal  (Figs.  34,  35  ),  or  tabular.    Cleav- 
age indistinct;   very  brittle;   fracture  conchoidal. 

Color  yellow,  greenish  or  reddish  yellow,  brown,  gray.  Streak  white, 
pale  yellow.  Luster  resinous,  greasy,  adamantine.  Transparent  to  trans- 
lucent. (See  p.  212.) 

In  beds  with  gypsum;  about  vents  of  volcanoes  and  fumaroles;  in  oxidized 
parts  of  sulphide  ores;  with  celestite,  gypsum,  calcite,  aragonite. 

2      G.  1.9  MELANTERITE, (Copperas,  Green  Vitriol),  FeSO4-7H2O. 

Struct. — Capillary,  fibrous,  compact,  stalactitic,  concretionary,  powdery; 
monoclinic  crystals  rare.  Cleavage  inconspicuous,  one  direction  crosswise 
(001);  brittle;  fracture  conchoidal,  earthy. 

Color  green,  yellowish  green,  white;  dull  yellowish  white  on  exposure. 
Streak  white.  Luster  vitreous,  dull.  Transparent  to  translucent.  Sweet 
astringent  taste.  (See  p.  218.) 

Oxidation  product  of  iron  sulphide  minerals — marcasite,  pyrite,  chal- 
copyrite,  pyrrhotite,  etc. 

2      G.  1.0-2.0    SEPIOLITE  (Meerschaum),  ILMgzSisO^;  sometimes  Cu  and  Ni. 
2\        Struct. — Compact,  nodular,  earthy,  clay-like,  rarely  fibrous;   floats  when 
dry.     Cleavage   none;    brittle;    fracture  conchoidal,  uneven;    smooth  feel; 
adheres  to  tongue. 

Color  white,  grayish,  yellowish.  Streak  white.  Luster  dull.  Opaque. 
(See  pp.  232,  254.) 

In  peridotites  and  serpentine  with  magnesite,  chlorite;  masses  in  stratified 
earthy  deposits. 

2      G.  3.6-3.8     Hydrozincite  (Zinc  Bloom),  Zn3(OH)4CO3;  Zn  60.8%. 
2%        Struct. — Earthy,     compact,     fibrous,    incrusting,    stalactitic.     Cleavage 
none;  brittle;  fracture  uneven,  splintery. 


SEC.  16]  PHYSICAL  TABLES  95 

H. 

Color  white,  gray,  yellow.  Streak  white.  Luster  dull,  pearly.  Opaque. 
(See  p.  248.) 

With  calamine,  smithsonite,  other  secondary  zinc  minerals,  sphalerite. 

2      G.  2.6-2.7     Pharmacolite  (Arsenic  Bloom),  HCaAsO4-2H2O. 
2|        Struct. — Fibrous,  acicular,  incrusting,  powdery;    small  prismatic  mono- 
clinic    crystals   rare.     Cleavage    distinct,    one   direction   lengthwise    (010); 
sectile;  thin  flakes  flexible;  fracture  uneven. 

Color  white,  grayish;  may  be  tinged  red  by  Co  or  green  by  Ni.      Streak 
white.     Luster  vitreous,  pearly.    Translucent  to  opaque.     (See  p.  228.) 
With  arsenopyrite  and  arsenical  ores  of  cobalt  and  silver. 

2*    G.  2.9-3.0    CRYOLITE,  Na3AlF6;  Na  32.8%;  Al  12.8%. 

Struct. — Cleavable,  granular,  compact;  rarely  small  monoclinic  crystals, 
like  cubes  and  octahedrons.  Cleavage  none;  often  parting  three  directions 
at  88°,  90°,  and  92°  (001)  (110);  brittle;  fracture  uneven. 

Color  white,  colorless,  brownish,  reddish.  Streak  white.  Luster  vitre- 
ous, greasy;  pearly  on  (001).  Transparent  to  translucent.  (See  p.  226.) 

Often  resembles  ice  or  paraffin.  In  veins  with  quartz,  siderite,  galena, 
sphalerite,  pyrite,  chalcopyrite,  fluorite. 


2  G.  2.0-2.2    DEWEYLITE  (Gymnite)  approx.  ILJVIg^SiOOs^HjO;  variable. 

3  Struct. — Amorphous,  like  gum  or  resin;  brittle;  often  much  cracked. 
Color  yellow,  white,  greenish,  reddish.     Streak  white.    Luster  greasy, 

resinous.    Translucent.     (See  pp.  232,  254.) 
In  serpentine  and  crystalline  limestone. 


2  G.  5.8-6.0    Bromyrile  (Bromargyrite),  AgBr;   Ag  57.4%. 

3  Struct. — Compact,    incrusting,    concretionary;     isometric    crystals   rare. 
Cleavage  none;  sectile;  fracture  uneven; 

Color  bright  yellow  to  amber-yellow,  greenish;  often  grass-green  or  olive- 
green  externally;  little  altered  on  exposure.  Streak  pale  yellow,  greenish 
yellow.  Luster  resinous,  adamantine.  Transparent  to  translucent.  (See 
p.  216.) 

With  cerargyrite,  embolite,  cerusite,  calcite,  in  oxidized  portions  of  silver 


G.  1.0-1.1    AMBER  (Succinite,  Retinite),  C2oH32O2. 

Struct. — Amorphous,  irregular  lumps,  grains;  fracture  conchoidal;  brittle; 
sometimes  inclusions  of  insects,  vegetable  remains,  liquids,  minerals. 

Color  yellow,  brownish  yellow,  brownish  red,  whitish.  Streak  white. 
Luster  greasy,  resinous.  Transparent  to  translucent.  Electrified  by  friction. 
(See  p.  212.) 

Fossil  resin  in  clays,  sands,  coal  beds,  sedimentary  rocks. 


96  DETERMINATIVE  MINERALOGY  [SEC.  16 

H. 

3      G.  6.6-7.2    VANADINITE,  Pb6Cl(VO4)3;    Pb  73%;  V2O6  19.4%;   sometimes 

P,  As. 

Struct. — Small  hexagonal  crystals  (prisms,  Fig.  49),  sometimes  hollow; 
fibrous,  incrusting,  compact,  globular.  Cleavage  none;  brittle;  fracture 
uneven,  conchoidal. 

Color  ruby-red,  brown,  yellow.  Streak  white,  pale  yellow.  Luster  greasy, 
resinous.  Translucent  to  opaque.  (See  p.  214.) 

In  oxidized  parts  of  lead  ores;  in  gold  and  silver  veins;  with  pyromorphite, 
wulfenite,  galena. 

3      G.  6.7-7.0    WULFENITE,  PbMoO4;  Pb  56.4%;  sometimes  Ca. 

Struct. — Thin  square  tabular  tetragonal  crystals;  sometimes  acute  pyram- 
idal; granular.  Cleavage  indistinct;  brittle;  fracture  conchoidal,  uneven.  - 

Color  yellow,  orange,  olive-green,  brown,  yellowish  gray,  whitish.  Streak 
white.  Luster  adamantine,  resinous.  Transparent  to  translucent.  (See 
p.  214.) 

In  oxidized  parts  of  lead  veins  with  galena,  pyromorphite,  vanadinite. 

3      G.  1.8-1.9    AIXOPHANE,  approx.  Al2SiO5-5H20;  variable. 

Struct. — Amorphous,  incrusting,  stalactitic;  fracture  conchoidal,  earthy; 
brittle. 

Color  sky-blue,  green,  yellow,  brown,  colorless.  Streak  white.  Luster 
vitreous,  waxy.  Translucent.  Resembles  opal.  (See  p.  252.) 

In  fissures  and  cavities  in  copper  and  iron  mines;  cavities  in  marls  and 
limestones. 

3      G.  6.4-6.6    CERUSITE  (White  Lead  Ore),  PbCO3;  Pb  77.5%. 
3£        Struct. — Pseudohexagonal   orthorhombic   crystals,    clusters,    star-shaped 
groups;    granular,  fibrous,  compact.     Cleavage  indistinct,    brittle;    fracture 
conchoidal. 

Color  white,  gray,  colorless;  or  yellow,  brown,  etc.,  from  impurities.  Streak 
white.  Luster  adamantine,  greasy,  silky.  Transparent  to  translucent. 
(See  p.  214.) 

In  oxidized  parts  of  lead  ores  with  lead,  zinc,  iron,  and  copper  minerals. 

3  G.  2.5-2.6    SERPENTINE,  EUMgsSijOgj    commonly  Fe,  sometimes  Ni. 

4  Struct. — Massive  compact,  fibrous  (chrysolite,  asbestos);    lamellar  (mar- 
molite);  columnar  (picrolite);  brittle;  fibers  flexible  and  tough;  fracture  con- 
choidal, splintery. 

Color  olive-green,  blackish  green,  yellowish  green,  yellow;  rarely  white. 
Streak  white.  Luster  greasy,  waxy,  silky.  Translucent  to  opaque.  (See 
pp.  232,  254.) 

Common  alteration  product  of  olivine  rocks  (peridotites) ;  in  dolomitic 
limestone;  with  magnetite,  talc,  chromite,  magnesite,  corundum,  platinum, 
diamond.  Mixed  with  dolomite,  calcite,  or  magnesite  in  a  mottled  or  clouded 
green  marble  (verdantique,  or  ophicalcite) . 


SEC.  16]  PHYSICAL  TABLES  97 

H. 

3  G.  4.3-4.4    WITHERITE,  BaCO3;  BaO  77.7%. 

4  Struct. — Compact,    granular,   radial  fibrous,  lamellar;    pseudohexagonal 
orthorhombic    crystals    resembling    quartz.     Cleavage    indistinct,     brittle; 
fracture  uneven. 

Color  white,  grayish,  yellowish.     Streak  white.    Luster  vitreous,  greasy. 
Transparent  to  translucent.     (See  p.  226.) 
In  veins  with  galena,  barite,  fluorite,  calcite. 

3*    G.  6.5-7.1    PYROMORPHITE  (Green  Lead  Ore),  Pb8Cl(P04)3;  Pb  76.3%; 
4  P206 15.7%. 

Struct. — Small  prismatic  hexagonal  crystals,  often  rounded,  barrel- 
shaped,  sometimes  hollow;  incrusting,  reniform,  disseminated.  Cleavage 
none;  brittle;  fracture  conchoidal,  uneven. 

Color  green,  yellow,  brown,  white,  gray.  Streak  pale  yellow,  greenish 
yellow,  white.  Luster  resinous,  greasy,  adamantine.  Translucent  to  opaque. 
(See  p.  214.) 

In  oxidized  parts  of  lead  veins  with  galena,  cerusite,  mimetite,  barite, 
limonite. 

3£    G.  2.6-2.8    ALTJNTTE      (Alum    Stone),     KAJ,(OH)e(SO«)2;       K2O  11.4%; 
4  A120337%. 

Struct. — Compact,  granular,  fibrous,  earthy;  hexagonal-rhombhedral 
crystals,  resembling  cubes,  rarely  tabular.  Cleavage  indistinct,  one  direction 
(0001);  brittle;  fracture  conchoidal,  splintery,  earthy. 

Color  white,  grayish,  reddish.  Streak  white.  Luster  vitreous,  pearly. 
Transparent  to  opaque.  (See  pp.  248,  256.) 

Veins  and  replacements  in  feldspathic  rocks  with  quartz,  kaolin,  pyrite, 
opal. 

3^    G.  2.3-2.4    WAVELLITE,  (A1OH)3(P04)2-5H20;  P205  34.5%;  sometimes  F. 
4          Struct. — Radial    fibrous,    globular   with    crystalline    surface,    stalactitic; 
distinct  orthorhombic  crystals  rare.     Cleavage  three  directions  at  73°,  90°, 
and  107°  (101)  (010);  brittle;  fracture  uneven,  conchoidal. 

Color  green,  yellow,  white,  brown.  Streak  white.  Luster  vitreous, 
pearly.  Translucent.  (See  pp.  252,  256.) 

In  clays  and  in  veins  and  joint  cracks  of  rocks;  with  oxides  of  iron  and  man- 
ganese, pyrite,  actinolite,  amblygonite. 

3£     G.  7.0-7.3     MIMETITE,  Pb5Cl(AsO4)3;  Pb  69.5%;  sometimes  Ca  and  P. 
4          Struct. — Prismatic,  tabular,  and  barrel-shaped  hexagonal  crystals;   globu- 
lar, reniform,  incrusting.     Cleavage  indistinct;  brittle;  fracture  uneven. 

Color  yellow,  orange,  brown,  colorless.  Streak  white.  Luster  greasy 
adamantine.  Translucent.  (See  p.  214.) 

In  oxidized  parts  of  lead  ores  with  galena  and  pyromorphite. 

3i     G.  3.1-3.3    SCORODITE,  FeAsO4-2H2O. 

4  Struct. — Pyramidal  orthorhombic  crystals,  sometimes  prismatic  or  tab- 
ular; botryoidal,  fibrous,  earthy,  amorphous.  Cleavage  imperfect,  two  direc- 
tions at  60°  and  120°  (120);  brittle;  fracture  conchoidal,  uneven. 


98  DETERMINATIVE  MINERALOGY  [SEC.  16 

H. 

Color  pale  green,  bluish  green,  blackish  green,  blue,  brown.  Streak 
white,  grayish,  greenish.  Luster  vitreous,  greasy.  Translucent.  (See  p. 
218.) 

With  arsenopyrite,  enargite,  limonite,  pyrite. 

4J  G.  3.1-3.2  APATITE  (Asparagus  Stone),  Ca5F(P04)3;  P2O8  42.3%; 
5  often  some  Cl. 

Struct. — Prismatic  hexagonal  crystals,  sometimes  tabular;  granular, 
compact.  Cleavage  indistinct,  one  direction  crosswise  (0001);  brittle;  frac- 
ture conchoidal,  uneven. 

Color  green,  blue,  violet,  red,  brown,  white,  colorless,.  Streak  white. 
Luster  vitreous,  greasy.  Transparent  to  opaque.  (See  pp.  228,  250.) 

In  crystalline  limestones  with  graphite,  fluorite,  pyrrhotite;  in  igneous 
rocks  (minute  crystals);  in  magnetite  ores;  with  fluorite  in  tin  and  tungsten 
ores;  amorphous  in  stratified  deposits  with  limestone  and  marl  (phosphorite, 
phosphate  rock,  phosphatic  nodules'). 

4}    G.  2.7-2.8    PECTOLITE,  HNaC2(SiO3)3;   sometimes  Mn. 
5          Struct. — Fibrous,  radiating,  compact;   rarely  distinct  monoclinic  crystals. 
Cleavage  two  directions  at  85°  and  95°  (100)  (001);  brittle;  fracture  splintery, 
uneven. 

Color  white,  grayish,  reddish.  Streak  white.  Luster  vitreous,  silky. 
Translucent  to  opaque.  (See  p.  234.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  zeolites,  prehnite,  datolite,  native  copper,  calcite,  quartz,  epidote, 
pyrite,  chalcopyrite,  chlorite. 

5  G.  4.3-4.5  SMITHSONITE  (Dry  Bone;  Calamine,  in  England),  ZnCO3; 
Zn  52.1%. 

Struct. — Mammillary,  stalactitic,  incrusting,  cellular  (dry  bone);  rarely 
small  hexagonal-rhombohedral  crystals  with  cleavage  distinct,  three  direc- 
tions at  72°  and  108°  (1011);  brittle;  fracture  uneven,  splintery. 

Color  white,  grayish,  colorless,  greenish,  blue,  pink,  brown.  Streak 
white.  Luster  vitreous,  adamantine,  pearly,  dull.  Transparent  to  opaque. 
(See  p.  248.) 

In  oxidized  zinc  ores,  usually  in  limestone  or  clay,  with  calamine,  cerusite, 
anglesite,  galena,  sphalerite,  calcite,  limonite. 

5      G.  2.2-2.3    ANALCITE  (Analcime,  a  zeolite),  NaAl(Si03)2-H2O. 
5|        Struct. — Isometric  crystals   (trapezohedrons,  Fig.  3);   granular,  compact. 
Cleavage  none;   brittle;   fracture  uneven,  conchoidal. 

Color  white,  colorless,  grayish,  greenish,  yellowish,  reddish.  Streak 
white.  Luster  vitreous.  Transparent  to  opaque.  (See  p.  232.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic  (sometimes  primary 
constituent  of  rock);  metalliferous  veins;  with  other  zeolites,  prehnite, 
datolite,  pectolite,  native  copper,  calcite,  quartz,  epidote,  pyrite,  chalcopy- 
rite, chlorite. 


SEC.  16]  PHYSICAL  TABLES  99 

H. 

5      G.  2.9-3.0    DATOLITE,  Ca(BOH)SiO4. 

5£        Struct. — Complex  monoclinic  crystals;    granular,   compact,    botryoidal 
(botryolite).     Cleavage  none;  brittle;  fracture  conchoidal,  uneven. 

Color  greenish,  colorless,  yellowish,  reddish,  grayish.  Streak  white. 
Luster  vitreous,  greasy,  dull.  Transparent  to  opaque.  (See  p.  230.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  metalliferous  veins; 
with  zeolites,  prehnite,  pectolite,  native  copper,  calcite,  quartz,  epidote 
pyrite,  chalcopyrite,  chlorite. 

5      G.  2.3-2.4    THOMSONITE  (a  zeolite),  (Ca,Na2)2Al4(SiO4)4-5H2O. 
5£        Struct. — Radial  fibrous,  columnar,  spherical  concretions,  compact;  rarely 
distinct    prismatic   orthorhombic    crystals,    striated    lengthwise.     Cleavage 
two  directions  lengthwise  at  90°  (100)  (010);  brittle;  fracture  uneven. 

Color  white,  colorless,  reddish,  green,  brown.  Streak  white.  Luster 
vitreous,  silky,  pearly.  Transparent  to  opaque.  (See  p.  230.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite, 
quartz,  epidote,  pyrite,  chalcopyrite,  chlorite. 

5      G.  4.9-5.3     MONAZITE,  (Ce,La,Nd,Pr)PO4;  also  Th,  Y;  ThO2  up  to  10%. 
5£        Struct. — Sands,    disseminated   grains;     small    monoclinic    crystals    rare. 
Cleavage  indistinct;  sometimes  parting  one  direction  (001) ;  brittle;  fracture 
conchoidal,  uneven. 

Color  yellow,  yellowish  green,  yellowish  brown,  reddish  brown.     Streak 
white.     Luster  resinous,   vitreous.     Translucent  to  opaque.     (See  p.  256.) 
In  pegmatite,  gneiss;    in  sands  of  streams  or  seashore;   with  magnetite 
ilmenite,  garnet,  corundum,  gold,  platinum. 


5  G.  2.1-2.3    SODALITE  (a  feldspathoid), 

6  Struct. — Compact,    disseminated     grains,    nodular;     isometric    crystals 
(dodecahedrons)  rare.     Cleavage  indistinct,  six  directions  at  60°,  90°,  and 
120°  (110);  brittle;  fracture  conchoidal,  uneven. 

Color  blue,   gray,   white,   red,   green.     Streak  white.    Luster  vitreous, 
greasy.     Transparent  to  translucent.     (See  p.  230.) 

In  igneous  rocks  with  nephelite,  leu  cite,  cancrinite;  not  with  quartz. 

5J     G.  2.4-2.5    LEUCITE  (Amphigene,  a  feldspathoid),  KAl(SiO3)2;  K2O  21.5% 
6          Struct. — Isometric  crystals  (trapezohedrons,  Fig.  3);    rounded  dissemi- 
nated grains.     Cleavage  indistinct;  brittle;  fracture  conchoidal. 

Color  white,  gray,  yellowish,  reddish,  colorless.     Streak  white.    Luster 
vitreous,  greasy.     Translucent  to  opaque.     (See  p.  254.) 

In  lavas  with  sanidine,  augite,  nephelite,  olivine;  not  with  quartz. 

5^     G.  3.9-4.1     Brookite  (Arkansite),  TiO2;  Ti  60%. 

6          Struct. — Orthorhombic  crystals,    often  tabular   (pseudohexagonal),  also 
prismatic,  faces  often  striated.     Cleavage  indistinct;  brittle;  fracture  uneven. 


100  DETERMINATIVE  MINERALOGY  [SEC.  16 

H. 

Color  hair-brown,  yellowish  and  reddish  brown  to  iron-black.  Streak 
white,  grayish,  yellowish,  brownish.  Luster  adamantine,  metallic.  Opaque 
(See  pp.  210,  262.) 

In  igneous  rocks,  gneiss,  crystalline  limestone;  in  veins  with  quartz 
feldspars,  metallic  sulphides;  with  rutile,  octahedrite,  titanite,  adularia, 
nephelite;  in  gold  placers. 

5|    G.  4.3-5.8    Fergusonite,  (Y,Er,Ce,U)(Cb,Ta)O4;  some  Ca,  Fe,  H2O. 
6          Struct. — Disseminated,    compact;     pyramidal    tetragonal    crystals    rare. 
Cleavage  none;   brittle;   fracture  conchoidal,  uneven. 

Color  brownish  black,  brown.  Streak  pale  brown.  Luster  submetallic, 
vitreous;  often  dull  outside.  Translucent  to  opaque.  (See  pp.  210,  264.) 

Brilliant  luster  of  fresh  fracture  in  striking  contrast  with  dull  surface.  In 
granite  and  pegmatite  with  quartz,  feldspars,  zircon,  allanite,  gadolinite;  in 
placer  gravels. 

5}    G.  2.1-2.2    OPAL,  Si02-nH2O;  H2O  2-16%,  chiefly  3-9%. 
6|        Struct. — Amorphous,  botryoidal,  reniform,  stalactitic,  earthy.     Cleavage 
none;   brttle;   fracture  conchoidal,  conspicuous  when  compact. 

Color  white,  yellow,  red,  brown,  green,  gray,  blue,  colorless;  sometimes  a 
rich  play  of  colors.  Streak  white.  Luster  vitreous,  pearly,  dull.  Trans- 
parent to  opaque.  (See  pp.  256,  260,  264.) 

In  cavities  and  veins  in  igneous  and  sedimentary  rocks.  For  description 
of  varieties,  see  p.  54. 

6      G.  3.1-3.2    CHONDRODITE,  Mg6(F,OH)2(Si04)2;  some  Fe  replaces  Mg. 
65        Struct. — Rounded  disseminated  grains,  compact;    small  complex  mono- 
clinic  crystals  rare.     Cleavage  sometimes  distinct,  one  direction  (001);  brittle; 
fracture  conchoidal,  uneven. 

Color  brownish  red,  yellow,  white.  Streak  white.  Luster  vitreous, 
greasy.  Translucent  to  opaque.  (See  p.  252.) 

In  crystalline  limestone  with  spinel,  magnetite,  pyroxene,  vesuvianite, 
phlogopite,  corundum. 

6  G.  4.1-4.3     RUTILE  (Nigrine),  TiO2;  Ti  60%;  often  Fe. 

7  Struct. — Prismatic  tetragonal  crystals,  striated  lengthwise;    knee-shaped 
and  rosette  twins;    acicular,  compact,  disseminated.     Cleavage  indistinct; 
brittle;  fracture  uneven. 

Color  red,  reddish  brown,  black  (deep  red  when  transparent).  Streak 
white,  gray,  pale  brown.  Luster  metallic,  adamantine.  Transparent  to 
opaque.  (See  pp.  210,  262.) 

In  veins  with  quartz,  feldspars,  hematite,  ilmenite;  hair-like  inclusions  in 
quartz;  in  igneous  contacts  and  metamorphic  rocks. 

6  G.  6.8-7.1     CASSITERITE  (Tinstone),  SnO2;    Sn  78.6%;    sometimes  Fe 

7  and  Ta. 

Struct. — Granular,  disseminated,  reniform  with  radiating  fibrous  struc- 
ture (wood  tin);  sand  and  pebbles  (stream  tin);  thick  prismatic  tetragonal 
crystals,  knee-shaped  twins  common  (Fig.  29).  Cleavage  indistinct;  brittle; 
fracture  uneven. 


SEC.  16]  PHYSICAL  TABLES  101 

H. 

Color  brown  to  black;  rarely  yellow,  red,  gray,  white.  Streak  white, 
grayish,  brownish.  Luster  adamantine,  greasy,  dull.  Transparent  to  opaque. 
(See  p.  262.) 

In  granite,  gneiss,  with  wolframite,  scheelite,  molybdenite,  tourmaline, 
fluorite,  topaz,  apatite,  lepidolite;  in  pegmatites;  in  sands  and  gravels. 

6  G.  4.0-4.5    Gadolinite,  FeGl2(YO)2(SiO4)2;  some  Ce,  La,  Nd,  Pr,  Er,  Sc,  etc. 

7  Struct. — Compact,   disseminated,   nodular;    rough  prismatic  monoclinic 
crystals  rare.     Cleavage  none;   brittle;  fracture  conchoidal,  splintery. 

Color  black,  greenish  black,  brown;  thin  splinters  grass-green  to  olive- 
green.  Streak  greenish  gray.  Luster  vitreous,  greasy.  Translucent  to 
opaque.  (See  pp.  232,  252.) 

In  granite  and  pegmatite  with  quartz,  mica,  allanite,  fergusonite,  fluorite, 
molybdenite. 

6|    G.  3.3.-S.5    VESUVIANITE    (Idocrase),  Ca6Al3(OH,F)(SiO4)8;   often  Mg, 

Fe,  Mn. 

Struct. — Short  prismatic  tetragonal  crystals  (Figs.  27,  28);  columnar, 
granular;  compact,  like  jade  (calif ornite) .  Cleavage  indistinct;  brittle; 
fracture  uneven. 

Color  brown  or  green,  rarely  yellow  or  blue.  Streak  white.  Luster  vitre- 
ous, greasy,  resinous.  Translucent  to  opaque.  (See  p.  244.) 

In  limestone  contacts  with  garnet,  pyroxene,  tourmaline,  chondrodite, 
wollastonite,  epidote. 

6|  G.  3.2-3.6  OLIVINE  (Chrysolite,  Peridot),  (Mg,Fe)2SiO4,  ranging  from 
7  For  sterile,  Mg2SiO4,  to  Fayalite,  Fe2SiO4;  sometimes  a  little 

.    x  Ni,  Sn,  Ti. 

Struct. — Granular,  disseminated;  prismatic  or  tabular  orthorhombic 
crystals  (Fig.  36)  rare.  Cleavage  indistinct,  two  directions  at  90°  (100)  (010); 
brittle;  fracture  conchoidal,  uneven. 

Color  yellowish  green,  yellowish  brown,  reddish.  Streak  white,  yellowish 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  p.  252.) 

In  basic  igneous  rocks  (gabbro,  basalt,  peridotite)  with  augite,  chromite, 
corundum,  spinel,  pyrope;  rarely  in  crystalline  dolomite. 

6£  G.  3.4-4.3  GARNET,  R"3R'"2(SiO4)3;  R"  =  Ca,  Mg,  Fe,  Mn;  R'"=A1, 
7£  Fe,  Cr,  sometimes  Ti. 

Struct. — Isometric  crystals  (dodecahedrons,  trapezohedrons,  Figs.  3,  7,  8); 
granular,  lamellar,  compact,  disseminated,  sand.  Cleavage  none;  parting 
sometimes  distinct,  six  directions  at  60°,  90°,  120°  (110);  brittle;  fracture 
conchoidal,  uneven. 

Color  red,  brown,  black,  etc.  (see  varieties  below).  Streak  white. 
Luster  vitreous.  Transparent  to  opaque.  (See  p.  244.) 

Pyrope,  Mg3Al2(SiO4)3;  deep  red  to  reddish  black,  rarely  purple;  sp.  g. 
3.7.  Rounded  grains  in  peridotite  and  serpentine. 

Almandite  (almandine),  Fe3Al2(SiO4)3;  deep  red  to  brownish  black;  sp.  g. 
3.9-4.2.  In  schists  and  gneiss  with  mica,  staurolite,  andalusite,  cyanite. 

Spessaritite,  Mn3Al2(SiO4)3;  brownish  red  to  hyacinth-red;  sp.  g.  4.0-4.3 


102  DETERMINATIVE  MINERALOGY  [SBC.  16 

H. 

In  granite  and  pegmatite  with  topaz,  tourmaline,  quartz,  orthoclase. 

Grossularite  (grossular,  cinnamon  stone,  essonite,  hessonite),  CasAUCSiO-Os; 
white,  yellow,  green,  pink;  sp.  g.  3.5-3.6.  In  limestone  contacts  with  wol- 
lastonite,  vesuvianite,  diopside,  scapolite. 

Andradite,  Ca3Fe2(SiO4)3;  wine-red,  greenish,  yellow,  brown,  black  (melan- 
ite);  sp.  g.  3.8-3.9.  In  phonolite,  nephelinite,  leucitophyre,  and  contacts, 
with  magnetite,  epidote,  feldspar,  nephelite,  leucite. 

Uvarovite,  or  Ca3Cr2(SiO4)3;  emerald-green,  small  crystals;  sp.  g.  3.4-3.5. 
In  peridotite,  serpentine,  with  chromite,  talc,  chlorite.  , 

Schorlomite,  Ca3(Fe,Ti)2(Si,Ti)4Oi2;  black,  sometimes  tarnished  to  pea- 
cock' tints;  sp.  g.  3.8-3.9;  streak  grayish  black.  Masses  in  nephelite 
syenite  with  brookite  and  crystals  of  other  black  garnets. 

Much  common  garnet  is  a  mixture  of  grossularite,  almandite,  and 
andradite. 

7      G.  2.65         QUARTZ  (Rock  Crystal},  Si02. 

Struct.  —  Prismatic  hexagonal  crystals  striated  crosswise,  commonly 
terminated  by  double  rhombohedron  (like  hexagonal  pyramid);  granular, 
disseminated,  compact.  Cleavage  indistinct;  brittle;  fracture  conchoidal. 

Color  white,  colorless,  and  various  shades  to  black  (see  varieties,  p.  55). 
Streak  white.  Luster  vitreous,  greasy.  Transparent  to  opaque.  (See  p. 
262.) 

In  igneous  rocks,  gneiss,  schist,  sand,  sandstone,  quartzite;  common  vein 
mineral  with  many  metallic  ores. 

7      G.  2.6-2.64    CHALCEDONY  (Agate,  Flint,  Hornstone,  Jasper),  Si02. 

Struct.  —  Compact,  botryoidal,  mammillary,  banded.  Cleavage  none; 
brittle  to  tough;  fracture  conchoidal. 

Color  white,  gray,  yellow,  red,  brown,  black  (see  varieties  p.  55).  Streak 
white.  Luster  waxy,  vitreous,  to  nearly  dull.  Translucent  to  opaque.  (See 
p.  262.) 

Lining  or  filling  cavities  (agate,  etc.);  concretions  in  chalk  (flint)  or  in 
limestone  (chert,  hornstone). 


G.  2.9-3.0    BORACITE, 

Struct.  —  Isometric-tetrahedral  crystals  (tetrahedron,  cube),  small,  iso- 
lated; groups  rare;  granular.  Cleavage  indistinct;  brittle;  fracture  con- 
choidal, uneven. 

Color  white,  colorless,  grayish,  yellow,  green.  Streak  white.  Luster 
vitreous.  Transparent  to  opaque.  (See  pp.  228,  242.) 

Commonly  disseminated  glassy  crystals  with  gypsum,  anhydrite,  halite, 
carnallite. 

G.  3.0-3.2    TOURMALINE,  R«Al3(BOH)2(Si06)4;R=Mg,Fe,Ca,Na,K,  Li. 
Struct.  —  Prismatic  hexagonal-rhombohedral  crystals,  hemimorphic,  curved 
triangular  in  cross-section,  striated  lengthwise  (Fig.  58)  ;  radiating,  columnar, 
compact.     Cleavage  indistinct;  brittle;  fracture  uneven,  conchoidal. 


SEC.  16]  PHYSICAL  TABLES  103 

H. 

Color  black  (schorl),  blue  (indicolite),  pink  to  red  (rubellite),  brown,  green; 
rarely  white  or  colorless  (achroite).  Streak  white.  Luster  vitreous,  resinous. 
Transparent  to  opaque.  (See  pp.  222,  242,  258.) 

In  pegmatite,  gneiss,  mica  schist,  slate,  gravels;  common  at  contacts; 
with  quartz,  feldspars,  beryl,  topaz,  cassiterite,  fluorite. 

7      G.  3.6-3.8    STAUROLITE    (Staurotide) ,    Fe(A10)4(AlOH)(SiO4)2;     some- 
7|  times  Mg,  Mn. 

Struct. — Prismatic  orthorhombic  crystals;  cross  twins  at  60°  and  90° 
common  (Figs.  31  to  33) ;  often  rough.  Cleavage  not  conspicuous,  one  direc- 
tion lengthwise  (010);  brittle;  fracture  conchoidal,  uneven. 

Color  yellowish  brown,  reddish  to  brownish  black,  weathering  gray. 
Streak  white  to  grayish.  Luster  vitreous,  dull.  Translucent  to  opaque. 
(See  p.  260.) 

In  slate,  schists,  gneiss,  with  garnet,  cyanite,  sillimanite,  tourmaline. 

7      G.  3.0  DANBURITE,  CaB2(Si04)2. 

7 \        Struct. — Prismatic    orthorhombic    crystals,    like    topaz;     disseminated. 
Cleavage  indistinct;   brittle;   fracture  uneven,  conchoidal. 

Color  wine-yellow,  yellowish  white,  yellowish  "brown.  Streak  white. 
Luster  vitreous,  greasy.  Transparent  to  translucent.  (See  p.  242.) 

With  calcite,  dolomite,  mica,  oligoclase,  microcline,  pyroxene,  tourmaline. 

7|    G.  4.5-4.8    ZIRCON,  ZrSiO4;  ZrO  67.2%;  commonly  a  little  Fe. 

Struct. — Square  tetragonal  crystals  with  prism  and  pyramid  ;•  irregular 
lumps,  disseminated  grains.  Cleavage  indistinct;  brittle;  fracture  uneven. 

Color  gray,  brown,  yellow,  green;  red  transparent  (hyacinth)',  colorless  or 
smoky  (jargon).  Streak  white.  Luster  adamantine,  vitreous.  Opaque  to 
transparent.  (See  p.  262.) 

Minute  grains  in  feldspathic  igneous  rocks;  rare  in  crystalline  limestone, 
gneiss,  schist;  with  magnetite,  apatite,  biotite,  wollastonite,  titanite;  in 
placers  with  gold,  corundum,  spinel,  garnet,  monazite. 

7£    G.  2.6-2.8    BERYL,  Gl3Al2(SiO3)6;  a  little  H,  sometimes  Na,  Li,  Cs. 
Rare  pink  varieties  (rose  beryl,  morganite).    See  p.  127. 

7£    G.  3.6-4.6    SPINEL,  MgAl2O4;  also  Fe,  Mn,  Cr,  Zn— see  varieties. 
8|        Struct. — Isometric    crystals    (octahedrons,  Fig.   1);    granular,  compact, 
disseminated.     Cleavage  indistinct;    brittle;   fracture  conchoidal. 

Color  red,  yellow,  green,  blue,  brown,  black  (see  varieties,  p.  127.)     Streak 
white.    Luster  vitreous,  dull.     Transparent  to  opaque.     (See  p.  262.) 
For  varieties,  occurrence,  and  associations,  see  p.  127. 

9      G.  3.9-4.1     CORUNDUM  (Adamantine  Spar),  A12O3. 
Brown,  pink,  and  ruby  varieties.     See  p.  45. 


104  DETERMINATIVE  MINERALOGY  [SEC.  17 


SECTION  17 

Streak  chalk-white,   colorless,  or  pale  colored;    mineral  green, 
blue,  or  violet;  distinct  cleavage  one  direction  only. 

H. 

1       G.  2.3-2.8    VERMICTJLITE     (Jefferisite,     Culsageeite,     etc.,     "  Cat     Gold." 
If  Hydrated  micas  and  chlorites;  silicates  of  Mg,  Fe,  Al. 

Struct. — Scaly,  flaky;  monoclinic  pseudomorphous  crystals.  Cleavage 
perfect,  one  direction  (001);  thin  flakes  flexible — some  very  slightly  so;  not 
elastic. 

Color  yellow,  yellowish  brown,  brownish  red,  yellowish  green,  dark  green. 
Streak  white.  Luster  pearly  to  nearly  dull,  metallic.  Translucent  to  opaque. 
(See  p.  232.) 

With  peridotite,  serpentine,  talc,  chlorite,  corundum,  micas. 

1  G.  2.8-2.9    PYROPHYLLITE  (Pencil  Stone),  H2Al2(Si03)2. 

2  Struct. — Foliated,  granular,  fibrous,  radial,    compact;    indistinct   ortho- 
rhombic  crystals  rare.    Cleavage  perfect,  one  direction  (001) ;  fracture  uneven, 
splintery;  thin  flakes  flexible,  not  elastic;  feel  greasy. 

Color  white,  apple-green,  gray,  yellow.  Streak  white.  Luster  pearly  to 
dull.  Translucent  to  opaque.  (See  p.  256.) 

In  schistose  rocks  with  cyanite,  topaz,  graphite,  lazulite. 

1      G.  2.5-2.8    TALC  (Steatite,  Soapstone,  Potstone),  H2Mg3(SiO3)4. 
3|        Struct. — Foliated,  granular;  fibrous  (agolite);  compact  (soft,  French  chalk; 
waxy,  rensselaerite);    indistinct  tabular  monoclinic  crystals  rare.     Cleavage 
perfect,  one  direction  (001);   sectile;    fracture  uneven;    thin  flakes  flexible, 
not  elastic;  greasy  feel. 

Color  apple-green,  gray,  white.  Streak  white.  Luster  pearly,  greasy. 
Transparent  to  opaque.  (See  pp.  236,  246,  256.) 

In  crystalline  schists  with  serpentine,  dolomite,  magnesite,  chlorite, 
actinolite, 

1  G.  2.6-3.0    CHLORITE  (Clinochlore,  Pennine,  Prochlorite),  H,  Fe,  Mg,  Al 
£5  silicates. 

Struct. — Foliated,  scaly,  granular,  compact,  earthy;  tabular  six-sided 
monoclinic  crystals  rare.  Cleavage  perfect,  one  direction  (001);  fracture 
scaly,  earthy;  thin  flakes  flexible,  tough,  not  elastic;  slight  soapy  feel. 

Color  light  to  dark  green.  Streak  white,  greenish  white,  grayish.  Luster 
pearly,  vitreous,  dull.  Translucent  to  opaque.  (See  pp.  236,  254.) 

In  schists,  greenstones,  green  slates,  serpentines,  peridotites;  with  mag- 
netite, chromite,  garnet,  talc,  pyroxene,  serpentine,  corundum. 

1|    G.  2.6-2.7    VIVIANITE  (Blue  Iron  Earth),  Fe3(PO4)2-8H2O;  P205  28.3%. 

2  Struct. — Radial  fibrous,  earthy;    prismatic  and  tabular  monoclinic  crys- 
tals.    Cleavage  distinct,  one  direction  (010);    sectile;    thin  flakes  flexible; 
fracture  splintery,  earthy. 


SEC.  17]  PHYSICAL  TABLES  105 

H. 

Color  blue,  green,  greenish  black;  colorless  when  fresh.  Streak  white, 
blue,  greenish  blue.  Luster  pearly  on  cleavage;  vitreous,  dull.  Transparent 
to  opaque.  (See  p.  104.) 

In  clay,  marl,  peat;  in  cavities  of  fossils;  with  limonite;  in  veins  with 
pyrrhotite,  pyrite,  gold. 

li    G.  2.1  COPIAPITE  (Misy),  Fe4(OH)2(S04)6  •  17H2O;  often  Al  and  Mg. 

2%  Struct. — Granular,  scales,  crusts,  powder;  six-sided  tabular  monoclinic 
crystals  rare.  Cleavage  one  direction  (010);  brittle;  fracture  uneven,  scaly, 
earthy. 

Color  yellow  to  greenish  and  brownish  yellow.  Streak  yellowish.  Luster 
pearly,  dull.  Translucent  to  opaque.  Disagreeable  metallic  taste.  (See 
p.  218.) 

With  iron  and  copper  sulphates  from  oxidation  of  sulphides. 

2      G.  2.9-3.0     ROSCOELITE    (Vanadium    Mica),    approx.    H2K(Al,V)3(SiO4)3; 

V2O3  20-29%;  some  Mg,  Fe. 
Struct. — Minute  micaceous  scales. 

Color  dark  green  to  brown.     Luster  pearly.     Translucent.     (See  p.  236.) 
In  veins  with  quartz,  gold,  and  tellurides;  disseminated  in  sandstone  with 
carnotite. 

2      G.  2.3-2.4     BRUCITE,  Mg(OH)2;   sometimes  Fe  and  Mn. 
2J        Struct. — Foliated,  scaly,  fibrous  (nemalite) ;  rarely  broad  tabular  hexagonal- 
rhombohedral  crystals.     Cleavage  perfect,  one  direction  (0001);  sectile;  thin 
flakes  and  fibers  flexible. 

Color  white,  grayish,  bluish,  greenish.  Streak  white.  Luster  pearly, 
on  cleavage;  vitreous,  waxy.  Transparent  to  translucent.  (See  pp.  248, 
252.) 

With  serpentine,  dolomite,  magnesite,  chromite. 

2      G.  1.7  BORAX  (Tinkal),  Na2B4O7-10H2O;   B2O3  36.6%. 

2\  Struct. — Compact,  earthy,  incrusting;  short  columnar  monoclinic  crystals. 
Cleavage  distinct,  one  direction  (100);  brittle;  fracture  conchoidal. 

Color  white,  colorless,  grayish,  bluish,  greenish.  Streak  white.  Luster 
vitreous,  greasy.  Translucent  to  opaque.  Sweetish  alkaline  taste.  (See 
pp.  226,  228.) 

In  mud  of  alkaline  lakes  and  marshes  with  halite,  gypsum,  colemanite. 

2  G.  2.7-3.0     MUSCOVITE  (Common  or  White  Mica,  Potash  Mica,  Isinglass), 

3  H2KAl3(SiO4)3;  often  a  little  Na,  Ca,  Mg,  Fe,  and  F. 
Struct. — Foliated,  flaky;  fine  scaly  to  fibrous  (sericite,  damourite);   dense 

(pinite);  rarely  distinct  monoclinic  (pseudohexagonal)  crystals.  Cleavage 
perfect,  one  direction  (001) ;  thin  flakes  tough,  very  elastic. 

Color  white,  gray,  yellowish,  greenish,  brownish.  Streak  white.  Luster 
vitreous,  pearly.  Transparent  to  translucent.  (See  p.  236.) 

In  pegmatite,  granite,  gneiss,  schists,  contacts;  with  feldspars,  quartz, 
tourmaline,  beryl,  garnet. 


106  DETERMINATIVE  MINERALOGY  [SEC.  17 

H. 

2  G.  2.8-3.1     BIOTITE   (Black  Mica,   Ferromagnesian  Mica), 

3  (H,K)2(Mg,Fe)2Al2(SiO4)3;  a  little  F,  often  Ti. 

Struct. — Plates,  scales;  pseudohexagonal  monoclinic  crystals  rare.  Cleav- 
age conspicuous,  one  direction  (001);  thin  flakes  tough,  very  elastic,  becom- 
ing more  brittle  with  alteration. 

Color  black,  brownish  black,  greenish  black,  dark  green.  Streak  white. 
Luster  pearly,  submetallic.  Transparent  to  opaque.  (See  pp.  204,  220,  236.) 

Common  in  granite,  syenite,  gneiss,  mica  schist;  less  common  in  basic 
igneous  rocks  and  contacts. 

2  G.  2.8-2.9    PHLOGOPITE  (Amber  Mica,  Bronze  Mica,  Magnesia  Mica), 

3  H2KMg3Al(SiO4)3;  some  F  and  Fe. 

Struct. — Plates,  scales;  prismatic  or  tabular  monoclinic  crystals  with 
hexagonal  or  orthorhombic  outlines,  commonly  rough.  Cleavage  conspicu- 
ous, one  direction  (001);  thin  flakes  tough,  very  elastic. 

Color  yellowish  brown,  brownish  red,  gray  to  green;  rarely  colorless. 
Streak  white.  Luster  pearly,  submetallic.  Translucent  to  transparent. 
(See  pp.  204,  236.) 

Contacts  in  crystalline  limestone;  in  serpentine;  with  pyroxene,  amphi- 
bole,  serpentine,  graphite,  apatite,  corundum. 

2  G.  2.8-2.9     LEPIDOLITE     (Lithia    Mica),    (Li,K)2Al2(OH,F)2(SiO3)3;    Li2O 

3  3.8-5.8  %. 

Struct. — Foliated,  scaly,  compact;  rarely  monoclinic  crystals,  small 
tabular  or  prismatic.  Cleavage  perfect,  one  direction  (001) ;  thin  flakes  tough, 
very  elastic. 

Color  pink,  lilac,  yellowish,  grayish  white,  white.  Streak  white.  Luster 
pearly.  Translucent.  (See  p.  236.) 

In  pegmatite  with  pink  and  green  tourmaline,  cassiterite,  topaz,  ambly- 
gonite,  spodumene. 

2  G.  2.8-2.9     Paragonite  (Soda  Mica),  H2NaAl3(SiO4)3. 

3  Struct. — Fine  scaly  masses,  compact;    strong  pearly  luster.     Otherwise 
like  muscovite,  above.     In  schists  with  cyanite,  staurolite,  tourmaline,  garnet, 
actinolite.     (See  p.  236.) 

2|    G.  6.2-6.5     Leadhillite,  Pb4(OH)2(CO3)2SO4. 

Struct. — Tabular  monoclinic  (pseudohexagonal)  crystals  and  twins; 
compact,  lamellar.  Cleavage  perfect,  one  direction  (001);  rather  sectile; 
fracture  conchoidal,  rarely  observable. 

Color  white,  colorless,  yellow,  green,  gray.  Streak  white.  Luster  pearly, 
adamantine.  Transparent  to  translucent.  (See  p.  214.) 

Twins  and  trillings  like  aragonite,  but  very  heavy.  Occurs  sparingly 
with  lead  ores. 

2i    G.  2.3-2.4    GIBBSITE  (Hydrargttlite),  A1(OH)3. 

85        Struct. — Stalactitic,    botryoidal,    fibrous   or   scaly   aggregates;     tabular 

monoclinic  (pseudohexagonal)  crystals  rare.     Cleavage  one  direction  (001), 

seldom  observable;  tough. 


SEC.  17]  PHYSICAL  TABLES  107 


Color  white,  grayish,  greenish,  reddish.  Streak  white.  Luster  vitreous, 
pearly,  dull.  Translucent.  (See  p.  256.) 

Chief  constituent  of  some  bauxite  deposits;  with  corundum,  natrolite, 
limonite. 

3  G.  2.5-2.8    TALC  (Steatite,  Soapslone,  Potstow),  H2Mg3(SiO3)4. 

4  Struct. — Foliated,  granular;  fibrous  (agolite)',  compact  (soft,  French  chalk; 
waxy,  rensselaerite) ;   indistinct  tabular  monoclinic  crystals  rare.     Cleavage 
perfect,  one  direction  (001) ;  thin  flakes  flexible,  not  elastic;  sectile:  fracture 
uneven;   greasy  feel.     Hardness  commonly  1-2|. 

Color  apple-green,  gray,  white.  Streak  white.  Luster  pearly,  greasy. 
Transparent  to  opaque.  (See  pp.  236,  246,  256.) 

In  crystalline  schists;  with  serpentine,  dolomite,  magnesite,  chlorite, 
actinolite. 

4£    G.  2.3-2.4    APOPHYLLITE  (H,K)2Ca(SiO3)2-H2O;  a  little  F. 

5  Struct. — Square  tabular  or  cifoe-like  tetragonal  crystals;  lamellar,  granular, 
compact.     Cleavage  perfect,  one  direction  (001);  brittle;  fracture  uneven. 

Color  white,  greenish,  yellowish,  reddish.  Streak  white.  Luster  vitreous; 
pearly  on  cleavage.  Transparent  to  nearly  opaque.  (See  p.  234.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite, 
quartz,  epidote,  pyrite  chalcopyrite,  chlorite. 

5  G.  3.3-3.5    HYPERSTHENE  (a  pyroxene),  (Fe,Mg)SiO3;  sometimes  Al. 

6  Struct. — Foliated,     cleavable,     granular;      orthorhombic     crystals    rare. 
Cleavage  perfect,  one  direction  (010),  less  distinct  two  directions  (110)  at 
46°,  88°,  92°,  and  134°;  brittle;  fracture  uneven. 

Color  grayish,  greenish,  and  brownish  black  to  bronze.  Streak  brownish 
gray,  grayish  white.  Luster  metalloidal  bronzy,  pearly.  Opaque  to  trans- 
lucent. (See  pp.  222,  258.) 

In  basic  igneous  rocks  with  plagioclase  feldspars,  olivine,  amphibole, 
pyroxene,  magnetite,  titanite;  seldom  with  quartz. 

6      G.  3.2-3.4    ZOISITE,  Ca2Al3(OH)(SiO4)3;  often  some  Fe. 
6|        Struct. — Columnar,   bladed,   fibrous,   compact;    prismatic  orthorhombic 
crystals  striated  lengthwise,  without  terminations.     Cleavage  conspicuous, 
one  direction  lengthwise  (010);   brittle;   fracture  uneven, 

Color  gray,  yellowish  brown,  greenish;    also  red  (thulite).     Streak  white. 
Luster  vitreous;  pearly  on  cleavage.     Transparent  to  opaque.    (See  p.  246.) 
In   crystalline   schists  with  hornblende,   vesuvianite,   cyanite,   epidote, 
garnet,  feldspars,  quartz, 

6  G.  3.2-3 .5    EPIDOTE  (Pistacite),  Ca2(Al,Fe)3(OH)(SiO4)3. 

7  Struct. — Long   monoclinic   crystals   striated  lengthwise,    commonly  ter- 
minated by  two  sloping  faces;  columnar,  divergent  acicular,  granular.     Cleav- 
age distinct,  one  direction  lengthwise  (001);   brittle;   fracture  uneven. 


108  DETERMINATIVE  MINERALOGY  [SEC.  17 

H. 

Color  yellowish  green  to  brown  and  black,  gray,  yellow,  red.  Streak 
white  to  grayish.  Luster  vitreous.  Transparent  to  opaque.  (See  pp.  222, 
246.) 

In  gneiss,  schist,  crystalline  limestone,  greenstone  with  garnet,  magnetite, 
chlorite,  native  copper,  zeolites. 

6  G.  3.2-3.3    SILLIMANITE  (FibrolUe),  Al2SiO6,  or  Al(AlO)SiO4. 

7  Struct. — Fibrous,    columnar,    radiating;     slender   orthorhombic    crystals 
without  terminations.     Cleavage   one  direction  lengthwise   (010);    brittle; 
fracture  splintery,  uneven. 

Color  grayish  white,  hair-brown,  greenish.  Streak  white.  Luster  vitre- 
ous, silky.  Transparent  to  translucent.  (See  p.  260.) 

In  gneiss;  in  contacts  of  aluminous  rocks  with  andalusite,  cordierite, 
garnets,  corundum. 

6  G.  3.3-3.5     DIASPORE,  A1O -OH;  Al  45%;  sometimes  Fe. 

7  Struct. — Scaly,    bladed,    fibrous;     columnar   and   tabular   orthorhombic 
crystals   rare.     Cleavage   distinct,    one   direction    (010);    brittle;    fracture 
conchoidal. 

Color  white,    grayish,    greenish,    hair-brown,    yellow,    colorless.     Streak 
white.     Luster  vitreous,  pearly.     Transparent  to  opaque.     (See  p.  260.) 
With  corundum,  emery,  dolomite,  margarite,  chlorite,  magnetite. 

6  G.  3.3-3.4    AXINITE,  HCa3Al2B(SiO4)4;   sometimes  Mn,  Fe,  Mg. 

7  Struct. — Tabular  wedge-shaped    triclinic    crystals    (Fig.  45);    lamellar, 
granular.     Cleavage  distinct,  one  direction  (010) ;  brittle;  fracture  conchoidal. 

Color  clove-brown,  yellow,  greenish,  grayish  blue,  gray.     Streak  white. 
Luster  vitreous.     Transparent  to  translucent.     (See  p.  242.) 
In  veins  with  quartz,  feldspars,  hornblende,  chlorite. 

6  G.  3.5-3.6    Chloritoid  (Ottrelite),  H2FeAl2SiO7;  some  Mg,  sometimes  Mn. 

7  Struct. — Foliated,  scaly,  rosette  groups;   rarely  tabular  triclinic  crystals, 
hexagonal  in  outline.     (Odrelite,  oblong  scales.)     Cleavage  perfect,  one  direc- 
tion (001);  thin  flakes  brittle. 

Color  dark  gray,  greenish  gray,  greenish  black.  Streak  white,  grayish,, 
pale  green.  Luster  pearly,  vitreous.  Translucent  to  opaque.  (See  pp.  222, 
258,  260.) 

In  hornfels,  slate,  schist,  with  chlorite,  hornblende,  garnet. 

7      G.  2.6-2.7     CORDIERITE   (lolite,   Dichroite,   Water  Sapphire), 

7|  (Mg,Fe)4Al8(OH)2(Si207)6. 

Struct. — Short  six-  or  twelve-sided  orthorhombic  (pseudohexagonal)  crys- 
tals; granular,  compact,  disseminated.  Cleavage  one  direction  lengthwise 
(010);  parting  sometimes  conspicuous  crosswise  (001);  brittle;  fracture 
uneven,  conchoidal. 

Color  light  to  dark  smoky  blue,  gray,  violet,  yellow.  Resembles  blue 
quartz;  often  altering  to  dull  green  chlorite;  transparent  varieties  show 
marked  difference  in  color  in  different  directions.  Streak  white.  Luster 
vitreous,  dull.  Transparent  to  translucent.  (See  pp.  244,  260.) 


SEC.  17,  18]  PHYSICAL  TABLES  109 

H. 

In  schists,  gneiss,  sometimes  in  granite;  with  quartz,  feldspars,  hornblende, 
tourmaline  andalusite,  sillimanite,  garnet. 

8      G.  3.4-3.6    TOPAZ,  A12(F,OH)  2SiO4. 

Struct. — Prismatic  orthorhombic  crystals,  many  striated  lengthwise; 
granular,  pebbles,  compact.  Cleavage  perfect,  one  direction  crosswise  (001); 
brittle;  fracture  conchoidal,  uneven. 

Color  white,  colorless,  yellow,  pink,  bluish,  greenish.  Streak  white.  Luster 
vitreous.  Transparent  to  opaque.  (See  p.  260.) 

Veins  in  pegmatite,  rhyolite,  granite;  contacts;  placers;  with  tourmaline, 
cassiterite,  apatite,  fluorite,  beryl,  garnet. 


SECTION  18 

Streak  chalk-white,   colorless,  or  pale  colored;    mineral  green, 
blue,  or  violet;   distinct  cleavage  two  directions. 


3|    G.  3.7  STRONTIANITE  (Strontian  Spar),  SrCO3;  SrO  70.1%;  some- 

4  times  Ca. 

Struct.-^Chisel-  or  spear-shaped  orthorhombic  crystals,  pseudohexagonal 
prisms;  columnar,  acicular,  fibrous,  divergent;  granular,  compact.  Cleavage 
distinct,  two  directions  at  63°  and  117°  (110);  brittle;  fracture  uneven. 

Color  white,  colorless,  grayish,  greenish,  yellowish.  Streak  white.  Luster 
vitreous,  greasy.  Transparent  to  translucent.  (See  p.  246.) 

In  ore  deposits  with  galena,  barite,  calcite,  celestite,  fluorite,  pyrite; 
veins  in  limestone,  chalk,  marl. 


4  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  Al2SiO6,  or  (AlO)2SiO3. 

5  Struct. — Long  tabular  or  bladed  triclinic  crystals  without  terminations; 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  lengthwise 
at  74°  and  106°  (100)  (010);  transverse  parting  (001)  common;  brittle;  frac- 
ture splintery. 

Color  blue,  white,  gray,  green  nearly  black;  often  streaked.  Streak 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  pp.  256,  260.) 

Hardness  lengthwise  4-5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum. 

4|     G.  3.4-3.5    CALAMINE  (Electric  Calamine,  Hemimorphite),  (ZnOH)2SiO3; 
5  Zn  54.2%. 

Struct.  —  Tabular  orthorhombic-hemimorphic  crystals,  commonly  diver- 
gent cockscomb  groups;  mammillary,  stalactitic,  granular.  Cleavage  two 
directions  lengthwise  at  76°  and  104°  (110);  brittle;  fracture  uneven,  con- 
choidal. 


110  DETERMINATIVE  MINERALOGY  [SEC.  18 

H. 

Color  white,  colorless,  yellowish,  brownish,  greenish,  bluish.  Streak  white. 
Luster  vitreous,  adamantine  dull.  Transparent  to  translucent.  (See  p.  252.) 

In  oxidized  zinc  ores,  usually  in  limestone  or  clay,  with  smithsonite, 
cerusite,  anglesite,  galena,  sphalerite,  calcite,  limonite. 

5      G.  3.4-3.6    TITANITE     (Spheric),  CaSiTiO5;  commonly  a  little  Fe. 
65        Struct. — Tabular  or  wedge-shaped  monoclinic  crystals;    lamellar,   com- 
pact.    Cleavage  distinct,  two  directions  at  665  and  113%°  (110);    parting 
often  distinct  four  directions  at  54°  and  126°  (221);   brittle;   fracture  con- 
choidal. 

Color  brown  to  black,  yellow,  gray,  green;  rarely  rose-red.  Streak  white. 
Luster  vitreous,  resinous,  adamantine.  Transparent  to  opaque.  (See  pp. 
234,  246.) 

Accessory  in  many  igneous  rocks;  in  gneiss,  chlorite  schist,  crystalline 
limestone;  with  chlorite,  iron  oxides,  pyroxene,  amphibole,  zircon,  apatite, 
quartz,  feldspars,  rutile. 

5  G.  2.9-3.4    HORNBLENDE    (an  amphibole),     Ca(Mg,Fe)3(SiO3)4,    with 

6  A12O3  up  to  15%  or  20%,  also  ferric  iron,  alkalies  (Na,  K), 
and  often  H  and  F. 

Struct. — Granular,  columnar,  fibrous,  radiated;  long  prismatic  mono- 
clinic  crystals,  often  rhombohedron-like  terminations;  prism  angle  124°; 
some  prisms  short,  six-sided.  Cleavage  perfect,  two  directions  lengthwise 
at  56°  and  124°  (110);  brittle;  fracture  uneven,  splintery. 

Color  green,  black,  brown,  gray.  Streak  brown,  green,  yellow,  gray, 
white.  Luster  submetallic,  vitreous,  pearly,  silky.  Translucent  to  opaque. 
(See  pp.  222,  238.) 

Common  in  igneous  and  metamorphic  rocks  with  feldspars,  pyroxenes, 
chlorite,  quartz,  calcite. 

5  G.  3.0-3.2    ACTINOLITE  (an  amphibole),  Ca(Mg,Fe)3(Si03)4. 

6  Struct. — Bladed    or    acicular    monoclinic    crystals;     columnar,    fibrous, 
divergent,  granular,  compact.     Cleavage  conspicuous,  two  directions  length- 
wise at  56°  and  124°  (110);  brittle;  fracture  splintery,  uneven. 

Color  bright  to  dark  green,  grayish  green.  Streak  white.  Luster  vitre- 
ous, silky,  pearly.  Transparent  to  opaque.  (See  p.  238.) 

In  talc,  chlorite,  and  hornblende  schists  and  greenstones,  with  epidote, 
talc,  serpentine. 

5  G.  3.0-3.2    Anthophyllite    (an    amphibole),    (Mg,Fe)SiO3;     sometimes  Al 

6  (Gedrite). 

Struct. — Lamellar,  columnar,  fibrous;  prismatic  orthorhombic  crystals  rare. 
Cleavage  two  directions  lengthwise  at  54^°  and  125£°  (110);  brittle;  fracture 
splintery;  fine  fibers  flexible  (asbestos). 

Color  gray,  clove-brown,  greenish  to  emerald.  Streak  white.  Luster 
vitreous,  pearly,  silky,  sometimes  metalloidal.  Translucent  to  opaque. 
(See  pp.  222,  238,  258.) 

In  schists  with  talc,  hornblende,  chlorite,  mica. 


SEC.  18]  PHYSICAL  TABLES  111 

H. 

5  G.  3.2-3.6    PYROXENE,     Ca(Mg,Fe)(SiO3)2,     ranging     from     Diopside, 

6  CaMg(SiO3)2,   to    Hedenbergite,  CaFe(SiO3)2;    often  some 
Al,  Mn,  and  Na. 

AUGITE  (a  pyroxene),  like  common  pyroxene  above,  with 
Al2OsUpto  15%  or  20%;  sometimes  alkali,  metals,  Na  and  K. 

Struct. — Granular,  columnar,  rarely  fibrous;  lamellar  (diallage);  thick 
monoclinic  prisms  four-  to  eight-sided  (Figs.  40,  41).  Cleavage  two  directions 
lengthwise  at  87°  and  93°  (110)  sometimes  distinct;  parting  often  prominent 
crosswise  (001);  diallage  has  fine  lamellar  parting  one  direction  lengthwise 
(100);  brittle;  fracture  uneven. 

Color  bright  to  dark  green,  grayish  green,  black,  brown.  Streak  greenish, 
brownish,  grayish  to  white.  Luster  vitreous,  submetallic,  dull.  Transparent 
to  opaque.  (See  pp.  220,  222,  240.) 

Common  in  basic  igneous  rocks;  in  crystalline  limestones  with  garnet, 
chlorite,  amphibole,  wollastonite,  magnetite,  pyrite. 

5  G.  3.2-3.6    DIOPSIDE  (Malacolite;   a  pyroxene),  CaMg(SiO3)2;  some  Fe. 

6  Struct. — Prismatic  monoclinic  (pseudotetragonal)  crystals,  stout,  termi- 
nated (Figs.  40,  41);   lamellar,  granular,  compact.     Cleavage  two  directions 
lengthwise  at  87°  and  93°  (110)  sometimes  distinct;  often  conspicuous  trans- 
verse parting  (001);  brittle;  fracture  uneven. 

Color  white,  colorless,  grayish,  green  to  black.  Streak  white,  grayish  to 
greenish.  Luster  vitreous,  dull.  Transparent  to  opaque.  (See  p.  240.) 

In  basic  igneous  rocks;  in  crystalline  limestones  with  wernerite,  vesuvian- 
ite,  garnet. 

5  G.  3.1-3.3    ENSTATITE  (a  pyroxene),  (Mg,Fe)SiO3;  FeO  up  to  12%. 

6  Struct. — Lamellar,  columnar,  fibrous,  compact;    prismatic  orthorhombic 
crystals  rare.     Cleavage  distinct,  two  directions  at  88°  and  92°  (110) ;  parting 
one  direction  (010),  bisecting  cleavage  angle;  brittle;  fracture  uneven. 

Color  grayish  white,  yellowish,  greenish,  to  olive-green  and  brown.  Streak 
white.  Luster  vitreous,  pearly;  submetallic,  bronzy  (bronzite).  Translucent 
to  opaque.  (See  pp.  240,  258.) 

In  basic  igneous  rocks  (gabbro,  peridotite)  and  in  serpentine. 

5  G.  3.3-3.5    HYPERSTHENE  (a  pyroxene),  (Fe,Mg)SiO3;  sometimes  Al. 

6  Struct. — Foliated,     cleavable,     granular;      orthorhombic     crystals    rare. 
Cleavage  perfect,  one  direction  (010),  less  distinct  two  directions  (110)  at 
46°,  88°,  92°,  and  134°;  brittle;  fracture  uneven. 

Color  grayish,  greenish,  and  brownish  black  to  bronze.  Streak  brownish 
gray,  grayish  white.  Luster  metalloidal  bronzy,  pearly.  Opaque  to  trans- 
lucent. (See  p.  222,  258.) 

In  basic  igneous  rocks  with  plagioclase  feldspars,  olivine,  amphibole, 
pyroxene,  magnetite,  titanite;  seldom  with  quartz. 

5i     G.  3.4-3.7    RHODONITE,  MnSiO3;   often  Ca,  Fe;   sometimes  Zn  (Fow- 

6^  lerite). 

Struct. — Granular,  cleavable,  compact;  tri clinic  crystals,  tabular,  com- 
monly rough,  with  rounded  edges.  Cleavage  distinct,  two  directions  at  87^° 
and  92j°  (110);  brittle,  tough  when  compact;  fracture  conchoiclal,  uneven. 


112  DETERMINATIVE  MINERALOGY  [Sec.  18 

H. 

Color  brownish  red,  flesh-red,  pink;  sometimes  yellowish  or  greenish; 
may  tarnish  brown  or  black  on  exposure.  Streak  white.  Luster  vitreous. 
Transparent  to  opaque.  (See  p.  240.) 

In  veins;  in  crystalline  limestone  with  willemite,  franklinite,  zincite. 

6      G.  3.0-3.1    AMBLYGONITE,  Li(AlF)PO4;  Li2O  10.1%;  often  Na;  sometimes 

OH. 

Struct. — Cleavable,  compact,  columnar;  triclinic  crystals  rare.  Cleavage 
conspicuous,  one  direction  (001),  less  distinct  in  another  plane  at  83°  and  97° 
to  this  (100);  brittle;  fracture  uneven. 

Color  white,  pale  gray,  green,  blue,  yellow,  brown.  Streak  white.  Luster 
vitreous;  pearly  on  (001).  Translucent  to  opaque.  (See  p.  242.) 

Resembles  feldspars,  but  heavier.  Rare  in  pegmatite  with  tourmaline,  . 
lepidolite,  apatite,  topaz. 

6  G.  2.5-2.6  ORTHOCLASE  (Potash  Feldspar),  KAlSi3O8;  K2O  16.9%; 
6|  often  Na. 

Struct. — Cleavable,  granular,  disseminated;  prismatic  and  tabular  mono- 
clinic  crystals  and  twins  (Figs.  42  to  44).  Cleavage  distinct,  two  directions 
at  90°  (010)  (001);  brittle;  fracture  conchoidal,  uneven. 

Color  white,  red,  gray,  green,  colorless.  Streak  white.  Luster  vitreous; 
often  pearly  on  cleavage.  Transparent  to  opaque.  (See  p.  238.)  For 
varieties,  see  p.  37. 

In  many  igneous  and  metamorphic  rocks;  in  veins  and  contacts;  with 
quartz,  other  feldspars,  mica,  hornblende,  pyroxene;  in  pegmatites  with 
beryl,  topaz,  tourmaline. 

6  G.  2.6-2.8  PLAGIOCLASE  (Soda-lime  and  Lime-soda  Feldspars'),  ranging 
6|  from  NaAlSisOg  (ab)  to  CaAl2Si2O8  (an),  generally  also 

some  K. 

Struct. — Lamellar,  granular,  disseminated;  small  triclinic  crystals  (Fig. 
46).  Cleavage  distinct,  two  directions  at  86°-86i°  and  94°-93£°  (001)  (010); 
often  striations  on  one  cleavage;  cleavage  often  curved;  brittle;  fracture 
uneven. 

Color  white,  colorless,  gray,  green,  bluish,  reddish;  sometimes  play  of 
colors — blue,  green,  yellow,  red.  Streak  white.  Luster  vitreous,  pearly. 
Transparent  to  opaque,  sometimes  opalescent.  (See  p.  238.)  For  descrip- 
tion of  varieties,  see  p.  37.) 

In  igneous  rocks,  gneisses,  schists,  with  other  feldspars,  quartz,  mica, 
chlorite,  zeolites;  sometimes  in  veins. 

6      G.  3.0-3.1    Glaucophane  (an  amphibole),  Na(Mg,Fe,Ca)Al(Si03)3. 
6|        Struct. — Columnar,    fibrous,    granular;     prismatic    monoclinic    crystals, 
commonly  indistinct.     Cleavage  distinct,  two  directions  lengthwise  at  58° 
and  122°  (110);   brittle,  small  fibers  flexible;   fracture  uneven,  conchoidal. 

Color  lavender-blue,  azure-blue,  bluish  to  grayish  black.  Streak  white. 
Luster  vitreous,  pearly,  silky.  Translucent  to  opaque.  (See  p.  238.) 

In  schists  and  gneisses  with  mica,  garnet,  epidote,  zoisite,  amphiboles, 
pyroxenes. 


SEC.  18]  PHYSICAL  TABLES  113 

H. 

6      G.  3.5-3.6     Aegirite  (Aegirine,  Acmite;  a  pyroxene),  NaFe'"(SiO3)2. 

6  \  Struct. — Long  prismatic  monoclinic  crystals  with  terminations  blunt 
(aegirite)  or  sharp  (acmite);  acicular,  fibrous.  Cleavage  distinct,  two  direc- 
tions at  87°  and  93°  (110);  brittle;  fracture  uneven. 

Color  greenish  black  to  reddish  and  brownish  black;  acmite  often  green 
interior,  brown  exterior.  Streak  pale  yellowish  gray.  Luster  vitreous, 
resinous.  Translucent  to  opaque.  (See  pp.  222,  240.) 

In  igneous  rocks  rich  in  soda  and  iron — aegirite  granite,  nephelite  syenite, 
phonolite,  pegmatite. 

6  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  Al2SiO6,  or  (AlO)2SiO3. 

7  Struct. — Long  tabular  or  bladed  triclinic  crystals  without  terminations, 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  length- 
wise at  74°  and  106°  (100)  (010);  transverse  parting  (001)  common;  brittle; 
fracture  splintery. 

Color  blue,  white,  gray,  green,  nearly  black;  often  streaked.  Streak  white. 
Luster  vitreous.  Transparent  to  translucent.  (See  pp.  256,  260.) 

Hardness  lengthwise  4-5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum. 

6  G.  3.1-3.2    SPODTJMENE  (a  pyroxene),  LiAl(SiO3)25  Li2O  8-4%;  some  Na. 

7  Struct. — Cleavable,    columnar,    compact;     rough  prismatic   or   flattened 
monoclinic  crystals,  striated  lengthwise.     Cleavage  conspicuous,  two  direc- 
tions lengthwise  at  87°  and  93°  (110);    parting  one  direction,  sometimes 
prominent,  bisecting  larger  cleavage  angle  (100);    brittle;    fracture  uneven, 
splintery. 

Color  white,  gray,  yellowish;  emerald-green  (hiddenite);  pink  to  purple 
(kuneite).  Streak  white.  Luster  vitreous,  pearly.  Transparent  to  opaque. 
(See  pp.  240,  242.) 

In  pegmatites  with  tourmaline,  lepidolite,  beryl,  amblygonite,  cassiterite. 

6£    G.3.2-3.a    OLIVINE   (Chrysolite,   Peridot),   (Mg,Fe)2SiO4;    ranging  from 
7  Forsterite,  Mg2SiO4,  to  Fayalite,  Fe2SiO4;  sometimes  a  little 

Ni,  Sn,  and  Ti. 

Struct. — Granular,  disseminated;  prismatic  or  tabular  orthorhombic 
crystals  (Fig.  36)  rare.  Cleavage  indistinct,  two  directions  at  90°  (100)  (010); 
brittle;  fracture  conchoidal,  uneven. 

Color  yellowish  green,  yellowish  brown,  reddish.  Streak  white,  yellowish 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  p.  252.) 

In  basic  igneous  rocks  (gabbro,  basalt,  peridotite)  with  augite,  chromite, 
corundum,  spinel,  pyrope;  rarely  in  crystalline  dolomite. 

6i     G.  3.1-3.2    ANDALUSITE  (Chiastolite,  Made),  Al2SiO5,  or  Al(AlO)SiO4. 

1\  Struct. — Columnar,  granular,  disseminated;  rough  orthorhombic  prisms, 
nearly  square.  Cleavage  two  directions  at  89°  and  91°  (110);  brittle;  frac- 
ture "uneven. 


114  DETERMINATIVE  MINERALOGY  [SEC.  18,  19 

H. 

Color  white,  pink,  reddish  brown,  olive-green;  sometimes  black  and  white 
cross  or  checkered  pattern  on  cross-fracture  (chiastolite,  or  made) .  Streak 
white.  Luster  vitreous,  dull.  Translucent  to  opaque.  (See  p.  260.) 

In  slate,  schists,  and  gneiss;  with  sillimanite,  garnet,  biotite,  tourmaline, 
cordierite. 

7|     G.  3.1  Lawsonite,  CaAl2(OH)4(SiO3)2. 

8         Streak. — Prismatic  or  tabular  orthorhombic  crystals;    lenticular  plates. 
Cleavage  perfect,  two  directions  at  90°  (010)  (001);  brittle;  fracture  uneven. 
Color  pale  blue,  bluish  gray,  colorless;  white  or  grayish  spots  due  to  altera- 
tion.    Streak    white.    Luster    vitreous,    greasy.    Transparent    to    opaque. 
(See  p.  244.) 

In  schists  with  glaucophane,  actinolite,  margarite,  epidote,  garnet. 

8|     G.  3.5-3.8    CHRYSOBERYL  (Cymophane),  G1A12O4. 

Struct. — Tabular  orthorhombic  crystals,  heart-shaped  or  pseudohexagonal 
twins,  disseminated  plates.  Cleavage  two  directions  at  60°  and  120°  (Oil); 
brittle;  fracture  uneven,  conchoidal. 

Color  yellowish  green,  deep  green,  greenish  white,  greenish  brown,  yellow. 
Streak  white.  Luster  vitreous,  greasy.  Transparent  to  translucent.  (See 
p.  260.) 

Alexandrite,  the  deep  green  variety,  is  red  by  gas  or  lamp  light;  cat's  eye 
is  yellowish  green,  opalescent. 

In  granite,  gneiss,  mica  schist,  placers;  with  beryl,  garnet,  tourmaline, 
sillimanite. 


SECTION  19 

Streak  chalk- white,  colorless,  or  pale  colored;    mineral  green, 
blue,  or  violet;   distinct  cleavage  three  or  more  directions. 

2  G.  2.1-2.6    HALITE  (Common  Salt,  Rock  Salt),  NaCl;   Na  60.6%;   often 
2|  Ca,  Mg. 

Struct. — Granular,  cleavable,  compact;  isometric  crystals  (cubes,  Fig.  5). 
Cleavage  distinct,  three  directions  at  90°  (100);  brittle;  fracture  conchoidal. 

Color  white,  colorless,  grayish,  reddish,  bluish.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  Taste  salty.  (See  p.  224.) 

Beds  in  sedimentary  strata  with  gypsum,  anhydrite,  sylvite,  calcite,  clay, 
sand;  in  dry  lakes;  in  brines. 

3  G.  1.9-2.0    SYLVITE,  KC1;  K  52.4%;  sometimes  Na. 

2|  Struct. — Granular,  compact;  isometric  crystals  (cubes,  Fig.  5).  Cleavage 
distinct,  three  directions  at  90°  (100);  brittle;  fracture  conchoidal. 

Color  white,  colorless,  grayish,  bluish,  reddish.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  Taste  salty,  bitter.  Becomes  damp 
in  moist  air.  (See  p.  224.) 

In  salt  deposits;  with  halite,  kainite,  carnallite. 


SEC.  19]  PHYSICAL  TABLES  115 

H. 

2J    G.  4.3-4.6    BARITE  (Barytes,  Heavy  Spar),  BaSO4;  sometimes  Ca  and  Sr. 
3£        Struct. — Tabular  and  prismatic  orthorhombic  crystals,  divergent  groups; 
compact,  lamellar,  fibrous.     Cleavage  distinct,  three  directions  at  78%°,  90°, 
and  101f°  (001)  (110);   brittle;  fracture  uneven. 

Color  white,  colorless,  light  shades  of  yellow,  brown,  red,  blue.  Streak 
white.  Luster  vitreous,  pearly.  Transparent  to  opaque.  (See  p.  226.) 

In  veins  with  galena,  sphalerite,  fluorite,  chalcopyrite;  in  limestones  and 
residual  clays  with  manganese  and  iron  oxides. 

3      G.  2.7          CALCITE  (Cole  Spar),  CaCO3;  often  Mg,  Fe,  Mn,  sometimes  Pb. 

Struct.  —  Hexagonal  -  rhombohedral  crystals,  prismatic,  scalenohedral, 
rhombohedral,  tabular,  or  acicular  in  habit  (Figs.  52  to  57);  rarely  twins; 
cleavable,  granular,  stalactitic,  oolitic,  earthy.  Cleavage  perfect,  three  direc- 
tions at  75°  and  105°  (lOll);  fracture  conchoidal,  seldom  observed;  brittle. 

Color  white,  colorless,  pale  shades  of  gray,  yellow,  red,  green,  blue,  violet; 
brown  to  black  when  impure.  Streak  white.  Luster  vitreous,  dull.  Trans- 
parent to  opaque.  (See  p.  246.) 

Chief  constituent  of  limestone,  marble,  chalk,  calcareous  marl;  in  veins 
with  metallic  ores,  quartz,  pyrite,  zeolites.  For  varieties  see  p.  40. 

3      G.  6.1-6.4    ANGLESITE  (Lead  Vitriol),  PbSO4;   Pb  63.3%. 

Struct. — Orthorhombic  crystals;  granular,  compact.  Cleavage  incon- 
spicuous, three  directions  at  76°,  90°,  and  104°  (001)  (110);  brittle;  fracture 
conchoidal . 

Color  white,  colorless,  gray,  brown,  green.  Streak  white.  Luster  adaman- 
tine, vitreous.  Transparent  to  translucent.  (See  p.  214.) 

In  oxidized  parts  of  ore  deposits  with  lead,  zinc,  and  iron  minerals. 

3  G.  3.9-4.0    CELESTITE,  SrSO4;  sometimes  Ca  and  Ba. 

3|  Struct. — Tabular  or  prismatic  orthorhombic  crystals  (Fig.  37);  fibrous, 
cleavable,  rarely  granular.  Cleavage  distinct,  three  directions  at  76°,  90°, 
and  104°  (001)  (110);  brittle;  fracture  uneven. 

Color  white,  colorless,  bluish,  reddish.  Streak  white.  Luster  vitreous, 
pearly.  Transparent  to  translucent.  (See  p.  226.) 

In  limestones  and  shales  with  gypsum,  halite,  sulphur,  galena,  aragonite. 

3|    G.  2.8-2.9    DOLOMITE,   CaMg(CO3)2;  sometimes  Fe  and  Mn  (much  Fe, 
Ankerite) . 

4  Struct. — Granular,  cleavable,  compact;  hexagonal-rhombohedral  crystals, 
faces  often  curved  (pearl  spar).     Cleavage  perfect,  three  directions  at  74°  and 
106°  (lOll);  brittle;  fracture  conchoidal,  uneven. 

Color  white,  colorless,  gray,  red,  green,  brown,  black.  Streak  white. 
Luster  vitreous,  pearly.  Transparent  to  opaque.  (See  p.  246.) 

Extensive  strata  as  dolomitic  limestone  and  marble;  gangue  with  ores  of 
lead,  zinc,  etc.;  with  serpentine,  talc,  gyspum,  and  ordinary  limestone. 

3|    G.  2.9-3.0    ARAGONITE  (Flos  Ferri),  CaCO3;  sometimes  Sr  and  Pb. 

4  Struct. — Chisel-  or  spear-shaped  orthorhombic  crystals,  pseudohexagonal 
prisms;  acicular,  columnar,  stalactitic,  coral-like.  Cleavage  three  directions 
at  64°,  90°,  and  116°  (110)  (010);  brittle;  fracture  conchoidal. 


116  DETERMINATIVE  MINERALOGY  [SEC.  19 


Color  white,  gray,  yellow,  pale  green,  violet.  Streak  white.  Luster  vitre- 
ous, resinous.  Transparent  to  translucent.  (See  p.  246.) 

In  beds  of  limonite,  siderite,  gypsum;  in  basalt,  serpentine;  with  celestite, 
sulphur,  metallic  sulphides,  zeolites;  constitutes  some  shells  (pearly  layers  of 
many),  and  coral. 

3|  G.  3.9-4.1  SPHALERITE  (Blende,  Zinc  Blende,  Jack,  Black  Jack,  Rosin 
4  Jack),  ZnS;  Zn  67%;  may  be  replaced  by  Fe  up  to  18%. 

Struct.  —  Cleavable  masses,  granular,  compact,  botryoidal;  rounded 
isometric-tetrahedral  crystals.  Cleavage  pronounced,  six  directions  at  60°, 
90°,  and  120°  (110);  brittle;  fracture  conchoidal. 

Color  yellow,  brown,  red,  green,  black;  rarely  white  or  pale  gray  (cleio- 
phane).  Streak  white,  light  to  dark  brown.  Luster  resinous,  adamantine, 
submetallic.  Transparent  to  opaque.  (See  pp.  200,  228,  250.) 

Ore  deposits  and  veins  with  galena,  pyrite,  chalcopyrite,  fluorite,  barite; 
also  in  limestones. 

4      G.  3.0-3.2    FLUORITE  (Fluor  Spar,  Blue  John),  CaF2;   F  48.9%;   some- 

times Cl. 

Struct.  —  Isometric  crystals  (cubes,  Figs.  5,  12),  penetration  twins;  cleavable 
masses,  granular,  columnar.  Cleavage  perfect,  four  directions  at  701°  and 
1095°  (111);  brittle;  fracture  uneven. 

Color  violet,  blue,  green,  yellow,  colorless,  brown.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  (See  p.  226.) 

Common  in  veins  and  contacts  with  galena,  sphalerite,  calcite,  barite, 
cassiterite,  apatite,  topaz,  lepidolite;  in  limestones;  rare  in  igneous  rocks. 

4  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  AlaSiOs,  or  (AlO),SiO,. 

5  Struct.  —  Long  tabular  or  bladed  triclinic  crystals  without  terminations; 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  lengthwise 
at  74°  and  106°  (100)  (010);  transverse  parting  (001)  common;  brittle;  frac- 
ture splintery. 

Color  blue,  white,  gray,  green,  nearly  black;  often  streaked.  Streak 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  pp.  256,  260.) 

Hardness  lengthwise  4-5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum. 

4£  G.  5.9-6.2  SCHEELITE,  CaWO4;  WO3  80.6%;  some  Mo;  sometimes  Cu 
5  (Cuproscheelite)  . 

Struct.  —  Small  pyramidal  tetragonal  crystals  resembling  octahedrons, 
sometimes  tabular;  incrusting,  granular,  compact.  Cleavage  distinct,  four 
directions  at  80°,  110°,  and  130^°  (111);  brittle;  fracture  conchoidal,  uneven. 

Color  white,  yellow,  brownish,  greenish,  reddish.  Streak  white  to  yellow- 
ish. Luster  greasy,  adamantine.  Transparent  to  translucent.  (See  pp.  234, 
254,  258.) 

In  veins,  and  contacts  with  quartz,  cassiterite,  topaz,  flourite,  apatite, 
molybdenite. 


SEC.  19]  PHYSICAL  TABLES  117 

H. 

5      G.  4.3-4.5    SMITHSONITE  (Dry  Bone;   Calamine,  in  England),  ZnC03; 

Zn52.1%. 

Struct.  —  Mammillary,  stalactitic,  incrusting;  cellular  (dry  bone);  rarely 
small  hexagonal-rhombohedral  crystals  with  cleavage  distinct  three  directions 
at  72°  and  108°  (lOll);  brittle;  fracture  uneven,  splintery. 

Color  white,  grayish,  colorless,  greenish,  blue  pink,  brown.  Streak 
white.  Luster  vitreous,  adamantine,  pearly,  dull.  Transparent  to  opaque. 
(See  p.  248.) 

In  oxidized  zinc  ores,  usually  in  limestone  or  clay,  with  smithsonite 
cerusite,  anglesite,  galena,  sphalerite,  calcite,  limonite. 

5  G.  2.5-2.6    NEPHELITE  (Nepheline,  Elaeolite,  a  feldspathoid),NaAlSiO4; 

6  also  K  (up  to  7%K2OX 

Struct.  —  Compact,  disseminated  grains;  small  hexagonal  crystals  rare. 
Cleavage  distinct,  three  directions  at  60°  and  120°  (10lO);  brittle;  fracture 
conchoidal,  uneven. 

Color  reddish,  brownish,  greenish,  gray,  white,  colorless.  Streak  white. 
Luster  greasy,  vitreous.  Transparent  to  opaque.  (See  p.  232.) 

In  lavas  and  granular  igneous  rocks  with  feldspars,  sodalite,  cancrinite, 
biotite,  zircon,  corundum;  not  with  quartz. 


5  G.  2.4-2.5     CANCRINITE  (a  feldspathoid), 

6  Struct.  —  Compact,  lamellar,  columnar,  disseminated;  prismatic  hexagonal 
crystals  rare.     Cleavage  distinct,  three  directions  at  60°  and   120°  (1010); 
brittle;  fracture  uneven. 

Color  white,  gray,  yellow,  green,  blue,  reddish.  Streak  white.  Luster 
vitreous,  greasy,  pearly.  Transparent  to  translucent.  (See  p.  230.) 

In  granular  igneous  rocks  with  nephelite,  sodalite,  biotite,  feldspars, 
titanite;  not  with  quartz. 


5  G.  2.6-2.8    WERNERITE  (ScapoK 

6  Struct.  —  Stout  prismatic  tetragonal  crystals;    compact,  fibrous,  granular. 
Cleavage  three  directions  lengthwise  at  45°  and  90°  (100)  (110)  not  conspicu- 
ous;  brittle;   fracture  conchoidal,  uneven. 

Color  white,  gray,  greenish,  bluish,  reddish.  Streak  white.  Luster 
vitreous,  greasy.  Translucent  to  opaque.  (See  pp.  234,  244.) 

In  crystalline  limestones  and  schists  with  pyroxenes,  amphiboles,  apatite, 
garnet,  biotite. 

5  G.  3.9-4.2    WILLEMITE,  Zn2SiO4;    Zn  58%;   may  contain   Mn  (Troostite)} 

6  some  Fe. 

Struct.  —  Compact,  granular,  disseminated  grains;  prismatic  hexagonal- 
rhombhedral  crystals  rare.  Cleavage  distinct,  three  directions  at  60°  and 
120°  (1120);  brittle;  fracture  conchoidal,  uneven. 

Color  yellow,  green,  red,  brown,  white.  Streak  white.  Luster  vitreous. 
Transparent  to  opaque.  (See  pp.  232,  252.) 

In  crystalline  limestone  with  franklinite,  zincite,  rhodonite. 


118  DETERMINATIVE  MINERALOGY  [SEC.  19 

H. 

5}    G.  3.8-3.9    Octahedrite  (Anatase),  TiO2;   Ti  60%. 

6  Struct. — Tetragonal  crystals,  pyramidal,  tabular,  rarely  prismatic;  Cleav- 
age distinct,  five  directions  at  82°,  111°,  and  136|°  (111)  (001);  brittle;  frac- 
ture uneven. 

Color  brown,  dark  blue,  black.  Streak  white,  pale  gray.  Luster  adaman- 
tine, metallic.  Translucent  to  opaque.  (See  pp.  210,  262.) 

Minute  crystals  in  granular  igneous  rocks;  in  gneiss,  schists,  quartzite, 
limestone;  with  brookite,  rutile,  ilmenite,  biotite,  adularia,  titanite,  gold. 

6  G.  3.5-3.7    CYANITE  (Kyanite,  Disthene),  Al2SiO6,  or  (AlO)2SiO3. 

7  Struct. — Long  tabular  or  bladed  triclinic  crystals  without  terminations, 
may  be  curved  or  radiating.     Cleavage  pronounced,  two  directions  length- 
wise at  74°  and  106°  (100)  (010);  transverse  parting  (001)  common;  brittle; 
fracture  splintery. 

Color  blue,  white,  gray,  green,  nearly  black;  often  streaked.  Streak  white. 
Luster  vitrtbus.  Transparent  to  translucent.  (See  pp.  256,  260.) 

Hardness  lengthwise  4-5,  crosswise  6-7.  In  gneiss  and  mica  schist  with 
staurolite,  garnet,  corundum. 

6£     G.  3.4-4.3     GARNET,  R^R'^SiO^;    R"=Ca,  Mg,  Fe,  Mn;    R"'=A1, 
7 1  Fe,  Cr,  sometimes  Ti. 

Struct. — Isometric  crystals  (dodecahedrons,  trapezohedrons,  Figs.  3,  7,  8); 
granular,  lamellar,  compact,  disseminated,  sand.  Cleavage  none;  parting 
sometimes  distinct,  six  directions  at  60°,  90°,  120°  (110);  brittle;  fracture 
conchoidal,  uneven. 

Color  red,  brown,  black,  etc.  (see  varieties,  p.  101).  Streak  white.  Luster 
vitreous.  Transparent  to  opaque.  (See  p.  244.) 

9  G.  3.9-4.1     CORUNDUM     (Adamantine  Spar],  A12O3. 

Struct. — Rough  hexagonal-rhombohedral  crystals,  prismatic,  pyramidal, 
tabular,  tapering  (barrel-shaped),  often  striated;  lamellar,  granular,  compact. 
Cleavage  none;  often  conspicuous  parting  three  directions  at  86°  and  940 
(lOll);  sometimes  transverse  parting  (0001);  brittle;  tough  when  compact; 
fracture  uneven,  conchoidal. 

Color  white,  gray,  brown  to  black;  deep  red  (ruby);  blue  (sapphire); 
black  from  admixture  of  magnetite,  hematite,  or  spinel  (emery).  Streak 
white.  Luster  vitreous,  adamantine.  Transparent  to  opaque.  (See  p.  260.) 

In  peridotite,  gneiss,  schist,  syenite,  crystalline  limestone;  with  olivine, 
chlorite,  serpentine,  magnetite,  spinel,  vermiculite;  cyanite,  diaspore,  musco- 
vite. 

10  G.  3.5  DIAMOND  (Carbon),  C. 

Struct. — Isometric  crystals  (octahedron,  hexoctahedron,  Figs.  1,  4), 
usually  with  curved  surfaces;  rounded  and  irregular  grains,  pebbles,  often 
with  radial  structure.  Cleavage  distinct,  four  directions  at  70^°  and  109|° 
(111);  brittle;  fracture  conchoidal. 


SEC.  19,  20]  PHYSICAL  TABLES  119 

H. 

Color  white,  colorless;  pale  shades  of  yellow,  red,  orange,  green,  blue, 
brown;  occasionally  black.  Streak  white.  Luster  adamantine,  greasy. 
Transparent  to  opaque.  (See  p.  264.) 

Bort,  grayish  to  black,  rough  rounded  masses  with  radial  or  confused 
crystalline  structure,  without  distinct  cleavage;  sp.  g.  3.5. 

Carbonado,  or  black  diamond,  granular  to  compact,  without  cleavage; 
sp.  g.  3.1-3.3. 

In  peridotite  or  serpentine;  in  sands,  gravels,  quartzite;  with  pyrope, 
magnetite,  chromite,  zircon,  gold. 

SECTION  20 

Streak  chalk-white,  colorless,  or  pale  colored;    mineral  green, 
blue,  or  violet;  no  distinct  cleavage. 

1      G.  5.5-5.6    CERARGYRITE  (Horn  Silver),  AgCl;  Ag  75.3%;  sometimes  Hg. 
1|        Struct. — Wax-like  crusts,  stalactitic,  dendritic;   isometric  (cubic)  crystals 
rare.     Cleavage  none;  highly  sectile;  fracture  conchoidal. 

Color  pearly  gray,  greenish,  colorless;  turns  violet,  brown  to  black  on 
exposure  to  light.  Streak  white,  grayish,  shiny.  Luster  waxy,  greasy, 
resinous.  Transparent  to  translucent.  (See  p.  216.) 

In  veins  with  other  silver  minerals,  calcite,  barite,  limonite. 

1      G.  5.3-5.8    EMBOLITE,  Ag(Cl,Br);  Ag  60-70%. 

1|        Struct. — Compact,    stalactitic,    concretionary;     isometric    crystals   rare. 
Cleavage  none;  sectile;  fracture  uneven. 

Color  yellow,  grayish  green,  yellowish  green,  becoming  darker  on  exposure. 
Streak  white.  Luster  resinous,  adamantine.  Transparent  to  translucent. 
(See  p.  216.) 

In  oxidized  parts  of  silver  veins  with  calcite,  barite,  limonite. 

1  G.  2.2-2.4    GLAUCONITE  (Greensand,  Green  Earth},  approx.  KFe(SiO3)2-H2O; 

2  K2O6-9%;  some  Al  and  Mg. 

Struct. — Granular,  earthy,  disseminated;  amorphous.  Cleavage  none; 
brittle;  fracture  earthy,  uneven. 

Color  yellowish  green,  grayish  green,  blackish  green.  Streak  light  green, 
greenish  white.  Luster  vitreous,  dull.  Opaque.  (See  p.  220.) 

Abundant  in  greensand  beds  (so-called  marls);  disseminated  in  sands, 
clays,  sandstones,  limestones. 

1  G.  0.9-1.0    OZOCERITE  (Mineral  Wax,  Native  Paraffin),  CnH2n+2. 

2  Struct. — Amorphous,    compact,  fibrous,  lamellar;  plastic,  may  be  sticky. 
Color  black,  brownish  black,  brownish  yellow,  leek-green.     Streak  yellow- 
ish brown,   pale  yellow.     Luster  waxy,   greasy,   submetallic.     Translucent, 
sometimes  greenish  opalescence.     Like  wax;  greasy  feel.     (See  p.  212.) 

Burns  with  bright  smoky  flame  and  odor  of  paraffin.  In  veins  in  sedi- 
mentary rocks. 


120  DETERMINATIVE  MINERALOGY  [SEC.  20 

H. 

1      G.  3.0-3.1    ANNABERGITE    (Nickel   Bloom,    Nickel  Ocher,    Nickel  Green), 

2%  Ni3(AsO4)2-8H20;  Ni  29.4%;  sometimes  Co  and  Ca. 

Struct. — Earthy,  in  crusting,  compact,  stains;  capillary  monoclinic  crys- 
tals rare.  Cleavage  none;  brittle;  fracture  uneven. 

Color  apple-green,  light  green.  Streak  pale  green,  greenish  white.  Luster 
dull,  vitreous.  Opaque  to  translucent.  (See  p.  218.) 

Oxidation  product  of  nickel  arsenides;  with  smaltite.  niccolite,  chloanthite, 
calcite. 

1  G.  2.3-2.8    GAKNIEBITE  ( Noumeite,  Genlhite),  approx.  H2(Ni,Mg)SiO4 •  nH2O ; 
J8J  Ni  8-35%. 

Struct. — Compact,  botryoidal,  incrusting,  earthy.  Cleavage  none;  frac- 
ture conchoidal,  earthy;  brittle.  Sometimes  greasy  feel.  Hardness  some- 
times 3-4. 

Color  pale  yellowish  green  to  emerald-green.  Streak  white,  greenish 
white.  Luster  greasy,  resinous,  dull.  Opaque.  (See  pp.  254,  258.) 

Veins  in  peridotites,  serpentine;  with  chromite,  talc,  chlorite. 

1|     G.  2.0-2.1    SULPHUR  (Brimstone),  S;  traces  of  Te,  Se,  As. 
2£        Struct. — Granular,   fibrous,   compact,   earthy;    reniform,   stalactitic,   in- 
crusting;  orthorhombic  crystals,  pyramidal  (Figs.  34,  35)  or  tabular.     Cleav- 
age indistinct;    brittle;    fracture  conchoidal. 

Color  yellow,  greenish  or  reddish  yellow,  brown,  gray.  Streak  white, 
pale  yellow.  Luster  resinous,  greasy,  adamantine.  Transparent  to  trans- 
lucent. (See  p.  212.) 

In  beds  with  gypsum;  about  vents  of  volcanoes  and  fumaroles;  in  oxi- 
dized parts  of  sulphide  ores;  with  celestite,  gypsum,  calcite,  aragonite. 

2  G.  1.9  MELANTERITE  (Copperas,  Green  Vitriol),  FeSO4-7H2O. 

Struct. — Capillary,  fibrous,  compact,  stalactitic,  concretionary,  powdery; 
monoclinic  crystals  rare.  Cleavage  inconspicuous,  one  direction  crosswise 
(001);  brittle;  fracture  conchoidal,  earthy. 

Color  green,  yellowish  green,  white;  dull  yellowish  white  on  exposure. 
Streak  white.  Luster  vitreous,  dull.  Transparent  to  translucent.  Sweet 
astringent  taste.  (See  p.  218.) 

Oxidation  product  of  iron  sulphide  minerals — marcasite,  pyrite,  chal- 
copyrite,  pyrrhotite,  etc. 

2      G.  2.6-2.7     Pharmacolite  (Arsenic  Bloom),  HCaAsO4-2H2O. 
2  5        Struct. — Fibrous,  acicular,  incrusting,  powdery;    small  prismatic  mono- 
clinic    crystals    rare.     Cleavage    distinct,    one    direction    lengthwise    (010): 
sectile;  thin  flakes  flexible;  fracture  uneven. 

Color  white,  grayish;   may  be  tinged  red  by  Co  or  green  by  Ni.      Streafc 
white.     Luster  vitreous,  pearly.     Translucent  to  opaque.     (See  p.  228.) 
With  arsenopyrite  and  arsenical  ores  of  cobalt  and  silver. 

2  G.  2.0-2.2     CIIRYSOCOLLA,  approx.  CuSiO3-2H2O;  variable;  Cu  20-50%. 

3  Struct. — Amorphous,     compact,     reniform,     incrusting,     stains,     earthy 
Cleavage  none;  brittle;  fracture  conchoidal. 


SEC.  20]  PHYSICAL  TABLES  121 

H. 

Color  green,  greenish  blue,  blue;  brown  to  black  from  impurities.  Streak 
white  to  pale  blue  or  green.  Luster  vitreous,  greasy,  dull.  Translucent  to 
opaque.  (See  p.  254.) 

In  oxidized  parts  of  copper  deposits,  with  malachite,  azurite,  cuprite, 
native  copper. 

2  G.  2.0-2.2     DEWEYLITE  (Gymni/e),  approx.  H4Mg4(Si04)3-4H2O;  variable. 

3  Struct. — Amorphous,  like  gum  or  resin;   brittle;  often  much  cracked. 
Color  yellow,  white,  greenish,  reddish.     Streak  white.    Luster  greasy, 

resinous.     Translucent.     (See  pp.  232,  254.) 
In  serpentine  and  crystalline  limestone. 

2  G.  5.8-6.0     Bromyrite  (Bromargyrite) ,  AgBr;   Ag  57.4%. 

3  Struct. — Compact,    incrusting,    concretionary;     isometric    crystals   rare. 
Cleavage  none;  sectile;  fracture  uneven. 

Color  bright  yellow  to  amber-yellow,  greenish;  often  grass-green  or  olive- 
green  externally;  little  altered  on  exposure.  Streak  pale  yellow,  greenish 
yellow.  Luster  resinous,  adamantine.  Transparent  to  translucent.  (See 
p.  216.) 

With  cerargyrite,  embolite,  cerusite,  calcite,  in  oxidized  portions  of  silver 


2£    G.  2.1-2.3    CHALCANTHITE     (Blue     Vitriol,     Copper     Vitriol,     Bluestone), 

CuSO4-5H2O;  Cu  25.4%. 

Struct. — Crystalline  crusts,  reniform,  stalactitic,  fibrous,  powdery;  small 
tabular  triclinic  crystals  rare.  Cleavage  indistinct;  brittle;  fracture  con- 
choidal,  earthy. 

Color  deep  blue,  sky-blue,  greenish  blue.  Streak  white.  Luster  vitreous, 
dull.  Translucent.  Plates  wet  iron  with  copper  by  contact.  Nauseous 
metallic  taste.  (See  p.  216.) 

In  oxidized  parts  of  copper  veins;  often  deposited  by  mine  waters. 

3      G.  6.7-7.0    WULFENITE,  PbMoO4;  Pb  56.4%;  sometimes  Ca. 

Struct. — Thin  square  tabular  tetragonal  crystals,  sometimes  acute  pyram- 
idal; granular.  Cleavage  indistinct;  brittle;  fracture  conchoidal.  uneven. 

Color  yellow,  orange,  olive-green,  brown,  yellowish  gray,  whitish.  Streak 
white.  Luster  adamantine,  resinous.  Transparent  to  translucent.  (See 
p.  214.) 

In  oxidized  parts  of  lead  veins  with  galena,  pyromorphite,  vanadinite. 

3      G.  1.8-1.9    ALLOPHANE,  approx.  Al2SiO5-5H2O;  variable. 

Struct. — Amorphous,  incrusting,  stalactitic;  brittle;  fracture  conchoidal, 
earthy. 

Color  sky-blue,  green,  yellow,  brown,  colorless.  Streak  white.  Luster 
vitreous,  waxy.  Translucent.  (See  p.  252.) 

Resembles  opal.  In  fissures  and  cavities  in  copper  and  iron  mines;  cavi- 
ties in  marls  and  limestones. 


122  DETERMINATIVE  MINERALOGY  [SEC.  20 

H. 

3  G.  2.5-2.6    SERPENTINE,  HiM&SiA;  commonly  Fe,  sometimes  Ni. 

4  Struct. — Massive  compact;  fibrous  (chrysotile,  asbestos);  lamellar  (marmo- 
liie);  columnar  (picrolite);  brittle;  fibers  flexible  and  tough.     Cleavage  none; 
fracture  conchoidal,  splintery. 

Color  olive-green,  blackish  green,  yellowish  green,  yellow;  rarely  white. 
Streak  white.  Luster  greasy,  waxy,  silky.  Translucent  to  opaque.  (See 
pp.  232,  254.) 

Common  alteration  product  of  olivine  rocks  (peridotites) ;  in  dolomitic 
limestone;  with  magnesite,  talc,  chromite,  magnetite,  corundum,  platinum, 
diamond.  Mixed  with  dolomite,  calcite,  or  magnesite  in  a  mottled  or  clouded 
marble  (verdantique,  or  ophicalcite). 


3  G.  2.3-2.8    GARNIERITE  (Noumeite,  Genthite),  approx.  H2(Ni,Mg)SiO4 •  nH2O; 

4  Ni  8-35%. 

Struct. — Compact,  botryoidal,  incrusting,  earthy.  Cleavage  none;  frac- 
ture conchoidal,  earthy;  brittle.  Sometimes  greasy  feel.  Hardness  some- 
times l-2f . 

Color  pale  yellowish  green  to  emerald-green.  Streak  white,  greenish 
white.  Luster  greasy,  resinous,  dull.  Opaque.  (See  pp.  254,  258.) 

Veins  in  peridotites,  serpentine;  with  chromite,  talc,  chlorite. 

3£  G.  6.5-7.1  PYROMORPHITE  (Green  Lead  Ore),  Pb6Cl(PO4)3;  Pb  76.3%; 
4  P206  15.7%. 

Struct. — Small  prismatic  hexagonal  crystals,  often  rounded,  barrel- 
shaped,  sometimes  hollow;  incrusting,  reniform,  disseminated.  Cleavage 
none;  brittle;  fracture  conchoidal,  uneven. 

Color  green,  yellow,  brown,  white,  gray.  Streak  pale  yellow,  greenish 
yellow,  white.  Luster  resinous,  greasy,  adamantine.  Translucent  to  opaque. 
(See  p.  214.) 

In  oxidized  parts  of  lead  veins  with  galena,  cerusite,  mimetite,  barite, 
limonite. 

3|    G.  2.3-2.4    WAVELLITE,  (A1OH)3(PO4)2-5H2O;   P2O6  34-5%;  sometimes  F. 
4          Struct. — Radial    fibrous,    globular   with    crystalline    surface,    stalactitic; 
distinct  orthorhombic  crystals  rare.     Cleavage  three  directions  at  73°,  90°, 
and  107°  (101)  (010);   brittle;   fracture  uneven,  conchoidal. 

Color  green,  yellow,  white,  brown.  Streak  white.  Luster  vitreous, 
pearly.  Translucent.  (See  pp.  252,  256.) 

In  clays  and  in  veins  and  joint  cracks  of  rocks;  with  oxides  of  iron  and 
manganese,  pyrite,  actinolite,  amblygonite. 

3£    G.  3.1-3.3    SCORODITE,  FeAs04-2H20. 

4  Struct. — Pyramidal  orthorhombic  crystals,  sometimes  prismatic  or  tabular; 
botryoidal,  fibrous,  earthy,  amorphous.  Cleavage  imperfect,  two  directions 
at  60°  and  120°  (120);  brittle;  fracture  conchoidal,  uneven. 

Color  pale  green,  bluish  green,  blackish  green,  blue,  brown.    Streak  white, 
grayish,  greenish.     Luster  vitreous,  greasy.     Translucent.     (See  p.  218.) 
With  arsenopyrite,  enargite,  limonite,  pyrite. 


SEC.  20]  PHYSICAL  TABLES  123 


4£  G.  3.1-3.2  APATITE  (Asparagus  Stone),  Ca6F(PO4)3;  P2O5  42.3%;  often 
5  some  Cl. 

Struct.  —  Prismatic  hexagonal  crystals,  sometimes  tabular;  granular, 
compact.  Cleavage  indistinct,  one  direction  crosswise  (0001);  brittle;  frac- 
ture conchoidal,  uneven. 

Color  green,  blue,  violet,  red,  brown,  white,  colorless.  Streak  white. 
Luster  vitreous,  greasy.  Transparent  to  opaque.  (See  pp.  228,  250.) 

In  crystalline  limestones  with  graphite,  fluorite,  pyrrhotite;  in  igneous 
rocks  (minute  crystals);  in  magnetite  ores;  with  fluorite  in  tin  and  tungsten 
ores;  amorphous  in  stratified  deposits  with  limestone  and  marl  (phosphorate, 
phosphate  rock,  phosphatic  nodules). 

5  G.  4.3-4.5  SMITHSONITE  (Dry  Bone;  Calamine,  in  England),  ZnCO3; 
Zn  52.1%. 

Struct.  —  Mammillary,  stalactitic,  incrusting;  cellular  (dry  bone);  rarely 
small  hexagonal-rhombohedral  crystals  with  cleavage  distinct  three  directions 
at  72°  and  108°  (lOll);  brittle;  fracture  uneven,  splintery. 

Color  white,  grayish,  colorless,  greenish,  blue,  pink,  brown.  Streak 
white.  Luster  vitreous,  adamantine,  pearly,  dull.  Transparent  to  opaque. 
(See  p.  248.) 

In  oxidized  zinc  ores,  usually  in  limestone  or  clay,  with  smithsonite, 
cerusite,  anglesite,  galena,  sphalerite,  calcite,  limonite. 

5      G.  2.9-3.0     DATOLITE,  Ca(BOH)SiO4. 

5|  Struct.  —  Complex  monoclinic  crystals;  granular,  compact,  botryoidal 
(botryolite).  Cleavage  none;  brittle;  fracture  conchoidal,  uneven 

Color  greenish,  colorless,  yellowish,  reddish,  grayish.  Streak  white. 
Luster  vitreous,  greasy,  dull.  Transparent  to  opaque.  (See  p.  230.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  metalliferous  veins; 
with  aeolites,  prehnite,  pectolite,  native  copper,  calcite,  quartz,  epidote, 
pyrite,  chalcopyrite,  chlorite. 

5      G.  2.2-2.3    ANALCITE  (Anakime,  a  zeolite),  NaAl(SiO3)2-H2O. 
5%        Struct.  —  Isometric  crystals  (trapezohedrons,  Fig.  3);    granular,  compact. 
Cleavage  none;  brittle;  fracture  uneven,  conchoidal. 

Color  white,  colorless,  grayish,  greenish,  yellowish,  reddish.  Streak  white. 
Luster  vitreous.  Transparent  to  opaque.  (See  p.  232.) 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic  (sometimes  primary 
constituent  of  rock);  metalliferous  veins;  with  other  zeolites,  prehnite, 
datolite,  pectolite,  native  copper,  calcite,  quartz,  epidote,  pyrite,  chalcopy- 
rite, chlorite. 

5      G.  2.3-2.4    THOMSONITE  (a  zeolite),  (Ca,Na2)2Al4(SiO4)4-5H2O. 

5|  Struct.  —  Radial  fibrous,  columnar,  spherical  concretions,  compact;  rarely 
distinct  prismatic  orthorhombic  crystals,  striated  lengthwise.  Cleavage  two 
directions  lengthwise  at  90°  (100)  (010);  brittle;  fracture  uneven. 

Color  white,  colorless,  reddish,  green,  brown.  Streak  white.  Luster 
vitreous,  silky,  pearly.  Transparent  to  opaque.  (See  p.  230.) 


124  DETERMINATIVE  MINERALOGY  [SEC.  20 

H. 

Amygdules  and  veins  in  igneous  rocks,  chiefly  basic;  in  metalliferous 
veins;  with  other  zeolites,  prehnite,  datolite,  pectolite,  native  copper,  calcite, 
quartz,  epidote,  pyrite,  chalcopyrite,  chlorite. 

5      G.  4.9-5.3     MONAZITE,  (Ce,La,Nd,Pr)P04;  also  Th,  Y;  Th02  up  to  19%. 
5|        Struct. — Sands,    disseminated    grains;     small    monoclinic    crystals    rare. 
Cleavage  indistinct;  sometimes  parting  one  direction  (001) ;  brittle;  fracture 
conchoidal,  uneven. 

Color  yellow,  yellowish  green,  yellowish  brown,  reddish  brown.  Streak 
white.  Luster  resinous,  vitreous.  Translucent  to  opaque.  (See  p.  256.) 

In  pegmatite,  gneiss;  in  sands  of  streams  or  seashore;  with  magnetite, 
ilmenite,  garnet,  corundum,  gold,  platinum. 

5  G.  2.1-2.3     SODALITE  (a  feldspathoid),  Na4Al3Cl(SiO4)3. 

6  Struct. — Compact,    disseminated    grains,    nodular;     isometric    crystal 
(dodecahedrons)  rare.     Cleavage  indistinct,  six  directions  at  60°,  90°,  and 
120°  (110);  brittle;  fracture  conchoidal,  uneven. 

Color  blue,  gray,  white,  red,  green.  Streak  white.  Luster  vitreous, 
greasy.  Transparent  to  translucent.  (See  p.  230.) 

In  igneous  rocks  with  nephelite,  leucite,  cancrinite;  not  with  quartz. 

5  G.  3.0-3.1     Lazulite  (Blue  Spar),  (Fe,Mg)(AlOH)2(PO4)2;  P2OB  45.4%. 

6  Struct. — Acute  pyramidal  or  tabular  monoclinic  crystals;   granular,  com- 
pact.    Cleavage  indistinct;   brittle;   fracture  uneven. 

Color  sky-blue,  pale  greenish  blue.  Streak  white.  Luster  vitreous. 
Translucent  to  opaque.  (See  p.  256.) 

In  veins  and  metamorphic  rocks  with  siderite,  corundum,  cyanite,  rutile. 

5|    G.  2.6-2.8    TUEQUOIS    (Turkis,    Turkish  Stone),  A12(OH)3PO4-H2O,  with 
6  1.5-6.5%  Cu. 

Struct. — Compact,  reniform,  stalactitic,  incrusting,  thin  seams,  dis- 
seminated; triclinic  crystals  rare.  Cleavage  none;  brittle;  fracture  con- 
choidal. 

Color  sky-blue,   bluish   green,   apple-green.     Streak  white,  pale  green. 
Luster  waxy,  dull.     Opaque  to  translucent.     (See  pp.  250,  256,  260.) 
Veins  and  seams  in  partly  decomposed  igneous  rocks. 

5£    G.  2.1-2.2    OPAL,  SiO2-wH20;  H2O  2-16%;  chiefly  3-9%. 
6j        Struct. — Amorphous,  botryoidal,  reniform,  stalactitic,  earthy.     Cleavage 
none;  brittle;  fracture  conchoidal,  conspicuous  when  compact. 

Color  white,  yellow,  red,  brown,  green,  gray,  blue,  colorless;  sometimes  a 
rich  play  of  colors.  Streak  white.  Luster  vitreous,  pearly,  dull.  Trans- 
parent to  opaque.  (See  pp.  256,  260,  264.) 

In  cavities  and  veins  in  igneous  and  sedimentary  rocks.  For  varieties, 
see  p.  54. 


SEC.  20]  PHYSICAL  TABLES  125 


5i     G.  3.0-3.3    JADE,  NaAl(SiO3)2  (Jadeite),  or  Ca(Mg,Fe)3(Si03)4  (Nephrite). 
6|         Struct.  —  Very  tough,  compact;  varieties  of  the  amphiboles,  tremolite  and 
actinolite  (nephrite)  or  of  the  pyroxene  jadeite.     Cleavage  none;    fracture 
splintery. 

Color  greenish,  grayish,  white.  Streak  white.  Luster  vitreous,  waxy, 
dull.  Translucent  to  opaque.  (See  pp.  238,  240.) 

Rolled  pebbles  in  clay;  ancient  or  oriental  utensils  and  art  objects.  Com- 
pare californite,  a  jade-like  compact  vesuvianite,  below. 

6      G.  2.8-3.0    PREHNITE,  H2Ca2Al2(SiO4)3;  often  some  Fe. 
65        Struct.  —  Botryoidal,  stalactitic,  radial  fibrous;  rounded  groups  of  tabular 
orthorhombic  crystals;  distinct  crystals  rare.     Cleavage  indistinct,  one  direc- 
tion (001)  ;  brittle;  fracture  uneven. 

Color  light  green,  oil-green,  gray,  white;  often  fading  on  exposure.     Streak 
white.  Luster  vitreous,  waxy.   Transparent  to  translucent.   (See  pp.  234,  244.) 
With  zeolites,  datolite,  apophyllite,  pectolite,  native  copper,  calcite,  quartz, 
epidote,  chlorite  —  in  igneous  rocks,  chiefly  basic. 

6|     G.  3.3-3.5    VESUVIANITE  (Idocrase),   Ca6Al3(OH,F)(SiO4)5;   often   Mg, 

Fe,  Mn. 

Struct.  —  Short  prismatic  tetragonal  crystals  (Figs.  27,  28);  columnar, 
granular,  compact,  like  jade  (californite).  Cleavage  indistinct;  brittle;  frac- 
ture uneven. 

Color  brown  or  green,  rarely  yellow  or  blue.  Streak  white.  Luster 
vitreous,  greasy,  resinous.  Translucent  to  opaque.  .  (See  p.  244.) 

In  limestone  contacts  with  garnet,  pyroxene,  tourmaline,  chondrodite, 
wollastonite,  epidote. 

6  G.  4.0-4.5    Gadolinite,  FeGl2(YO)2(SiO4)2;  some  Ce,  La,  Nd,  Pr,  Er,  Sc,  etc. 

7  Struct.  —  Compact,   disseminated,   nodular;    rough  prismatic  monoclinic 
crystals  rare.     Cleavage  none;   brittle;   fracture  conchoidal,  splintery. 

Color  black,  greenish  black,  brown;  thin  splinters  grass-green  to  olive- 
green.  Streak  greenish  gray.  Luster  vitreous,  greasy.  Translucent  to 
opaque.  (See  pp.  232,  252.) 

In  granite  and  pegmatite  with  quartz,  mica,  allanite,  fergusonite,  fluorite, 
molybdenite. 

6|    G.  3.2-3.6    OLIVINE  (Chrysolite,  Peridot),  (Mg,Fe)2SiO4;    ranging   from 
7  For  sterile,  Mg2SiO4,  to  Fayalite,  Fe2SiO4;  sometimes  a  little 

Ni,  Sn,  and  Ti. 

Struct.  —  Granular,  disseminated;  prismatic  or  tabular  orthorhombic 
crystals  (Fig.  36)  rare.  Cleavage  indistinct,  two  directions  at  90°  (100)  (010)  ; 
brittle;  fracture  conchoidal,  uneven. 

Color  yellowish  green,  yellowish  brown,  reddish.  Streak  white,  yellowish 
white.  Luster  vitreous.  Transparent  to  translucent.  (See  p.  252.) 

In  basic  igneous  rocks  (gabbro,  basalt,  peridotite)  with  augite,  chromite, 
corundum,  spinel,  pyrope;  rarely  in  crystalline  dolomite. 


126  DETERMINATIVE  MINERALOGY  [SEC.  20 

H. 

6|    G.  3.4-4.3    GARNET,  R3"R2  '"(SiO4)»;   R"=Ca,  Mg,  Fe,  Mn;    R'"=A1, 

7  5  Fe,  Cr,  sometimes  Ti. 

Struct. — Isometric  crystals  (dodecahedrons,  trapezohedrons,  Figs.  3,  7, 
8);  granular,  lamellar,  compact,  disseminated,  sand.  Cleavage  none;  parting 
sometimes  distinct,  six  directions  at  60°,  90°,  and  120°  (110);  brittle;  fracture 
conchoidal,  uneven. 

Color  red,  brown,  black,  green,  purple,  etc.  (See  varieties,  p.  101.)  Streak 
white.  Luster  vitreous.  Transparent  to  opaque.  (See  p.  244.) 

For  varieties  and  occurrence,  see  p.  101. 

7      G.  2.65         QUARTZ  (Rock  Crystal),  SiO2. 

Struct. — Prismatic  hexagonal  crystals  striated  crosswise,  commonly 
terminated  by  double  rhombhedron  (like  hexagonal  pyramid);  granular, 
disseminated,  compact.  Cleavage  indistinct;  brittle;  fracture  conchoidal. 

Color  white,  colorless,  and  various  shades  (see  varieties,  p.  55).  Streak 
white.  Luster  vitreous,  greasy.  Transparent  to  opaque.  (See  p.  262.) 

For  varieties  and  occurrence,  see  p.  55. 

7      G.  2.6-2.64     CHALCEDONY  (Agate,  Flint,  Hornstone),  SiO2. 

Struct. — Compact,  botryoidal,  mammillary,  banded.  Cleavage  none; 
brittle  to  tough;  fracture  conchoidal. 

Color  white,  grayish,  and  various  shades  (see  varieties,  p.  55).  Streak 
white.  Luster  waxy,  vitreous  to  nearly  dull.  Translucent  to  opaque.  (See 
p.  262.) 

For  varieties  and  occurrence,  see  p.  55. 

7      G.  2.9-3.0    BORACITE,  Mg7Cl2B16O30. 

Struct. — Isometric-tetrahedral  crystals  (tetrahedron,  cube),  small,  isolated; 
groups  rare;  granular.  Cleavage  indistinct;  brittle;  fracture  conchoidal, 
uneven. 

Color  white,  colorless,  grayish,  yellow,  green.  Streak  white.  Luster  vit- 
reous. Transparent  to  opaque.  (See  pp.  228,  242.) 

Commonly  disseminated  glassy  crystals  with  gypsum,  anhydrite,  halite, 
carnallite. 

7      G.  3.0-3.2    TOURMALINE,  R9Al3(BOH)2(SiO5)4;  R  =  Mg,  Fe,  Ca,  Na,  K,Ia. 
7|        Struct. — Prismatic  hexagonal-rhombohedral  crystals,  hemimorphic,  curved 
triangular  in  cross-section,  striated  lengthwise  (Fig.  58) ;  radiating,  columnar, 
compact.     Cleavage  indistinct;   brittle;   fracture  uneven,  conchoidal. 

Color  black  (schorl),  blue  (indicolite),  pink  to  red  (rubellite)  brown,  green; 
rarely  white  or  colorless  (achroite).  Streak  white.  Luster  vitreous,  resinous 
Transparent  to  opaque.  (See  pp.  222,  242,  258.) 

In  pegmatite,  gneiss,  mica  schist,  slate,  gravels;  common  at  contacts; 
with  quartz,  feldspars,  beryl,  topaz,  cassiterite,  fluorite. 

71    G.  4.5-4.8    ZIRCON,  ZrSiO4;  ZrO67.2%;  commonly  a  little  Fe. 

Struct. — Square  tetragonal  crystals  with  prism  and  pyramid;  irregular 
lumps,  disseminated  grains.  Cleavage  indistinct;  brittle;  fracture  uneven. 


SEC.  20]  PHYSICAL  TABLES  127 

H. 

Color  gray,  brown,  yellow,  green;  red  transparent  (hyacinth)',  colorless  or 
smoky  (jargon).  Streak  white.  Luster  adamantine,  vitreous.  Opaque  to 
transparent.  (See  p.  262.) 

Minute  grains  in  feldspathic  igneous  rocks;  rare  in  crystalline  limestone, 
gneiss,  schist;  with  magnetite,  apatite,  biotite,  wollastonite,  titanite;  in 
placers  with  gold,  corundum,  spinel,  garnet,  monazite. 


7|    G.  2.6-2.8    BERYL,  GLA^SiOs^;  a  little  H,  sometimes  Na,  Li,  Cs. 

8  Struct.  —  Prismatic  hexagonal  crystals,   often  large  rough,  and  striated 
lengthwise   (Fig.  49);    columnar,  granular,   compact.     Cleavage  indistinct; 
brittle;  fracture  uneven,  conchoidal. 

Color  bright  green  (emerald),  blue,  greenish  blue  (aquamarine),  yellow 
(golden  beryl),  pink  (rose  beryl,  morganite),  colorless.  Streak  white.  Luster 
vitreous.  Transparent  to  translucent.  (See  pp.  244,  260.) 

In  pegmatite;  less  common  in  granite,  mica  schist,  slate;  in  bituminous 
limestone;  with  topaz,  tourmaline,  garnet,  chrysoberyl,  rutile. 

7|  G.  3.6-4.6  SPINEL,  MgAl2O4;  also  Fe,  Mn,  Cr,  Zn-^see  varieties  below. 
8|  Struct.  —  Isometric  crystals  (octahedrons,  Fig.  1);  granular,  compact, 
disseminated.  Cleavage  indistinct;  brittle;  fracture  conchoidal. 

Color  red,  yellow,  green,  blue,  brown,  black  (see  varieties  below)  .  Streak 
white.  Luster  vitreous,  dull.  Transparent  to  opaque.  (See  p.  262.) 

Ruby  spinel,  MgAl2O4,  includes  the  red  and  reddish  transparent  to  trans- 
lucent varieties:  spinel  ruby,  deep  red;  balas  ruby,  rose-red;  rubicelle,  yellow 
to  orange  red;  almandine,  violet;  sp.  gr.  3.5-3.6.  In  gem  placers  with  zircon, 
garnet,  magnetite;  sometimes  in  crystalline  limestone. 

Pleonaste  (ceylonite),  (Mg,Fe)Al2O4,  dark  green,  brown  to  black,  blue; 
opaque  or  nearly  so;  sp.  gr.  3.5-3.6.  Chlorospinel,  Mg(Al,Fe)2O4,  grass- 
green;  sp.  gr.  3.6.  Gahnite,  ZnAl2O4,  dark  green,  greenish  black,  bluish  black, 
yellowish,  grayish  brown;  streak  grayish;  sp.  gr.  4.0-4.6.  Hercynite,  FeAl2O4, 
black;  streak  dark  grayish  green  to  leek-green;  sp.  gr.  3.9-4.0.  In  crystal- 
line limestone,  limestone  contacts,  basic  igneous  rocks,  placers;  with  calcite, 
chondrodite,  serpentine,  brucite,  olivine,  corundum,  graphite,  pyroxenes, 
phlogopite. 

Picotite,  (Mg,Fe)  (Al,Fe,Cr)2O4,  grading  into  chromite;  dark  yellowish 
brown  to  greenish  brown;  translucent  to  nearly  opaque;  sp.  gr.  4.1.  In 
peridotite,  serpentine;  with  pleonaste,  chromite,  talc,  chlorite,  corundum. 

9  G.  3.9-4.1     CORUNDUM  (Adamantine  Spar),  A12O3. 

Struct.  —  Rough  hexagonal-rhombohedral  crystals,  prismatic,  pyramidal, 
tabular,  tapering  (barrel-shaped),  often  striated;  lamellar,  granular,  compact. 
Cleavage  none;  often  conspicuous  parting  three  directions  at  86°  and  94° 
(lOll);  sometimes  transverse  parting  (0001);  brittle;  tough  when  compact; 
fracture  uneven,  conchoidal. 

Color  white,  gray,  brown  to  black;  deep  red  (ruby);  blue  (sapphire); 
black  from  admixture  of  magnetite,  hematite,  or  spinel  (emery).  Streak 
white.  Luster  vitreous,  adamantine.  Transparent  to  opaque.  (See  p.  260.) 

In  peridotite,  gneiss,  schist,  syenite,  crystalline  limestone;  with  olivine, 
chlorite,  serpentine,  magnetite,  spinel,  vermiculite;  cyanite,  diaspore,  musco- 
vite. 


128  DETERMINATIVE  MINERALOGY  [SEC.  21 

SECTION  21 

Streak  yellow,  red,  or  brown;  mineral  black  or  nearly  so. 

H. 

1  G.  0.9-1.0    OZOCERITE  (Mineral  Wax,  Native  Paraffin),  CnH2n+2. 

2  Struct. — Amorphous,  compact,  fibrous,  lamellar;  plastic;  may  be  sticky. 
Color  black,  brownish  black,  brownish  yellow,  leek-green.     Streak  yellow- 
ish brown,   pale  yellow.     Luster  waxy,   greasy,   submetallic.     Translucent, 
sometimes  greenish  opalescence    Like  wax;   greasy  feel.     Burns  with  bright 
smoky  flame  and  odor  of  paraffin  (See  p.  212.) 

In  veins  in  sedimentary  rocks. 

1  G.  1.0-1.8.    ASPHALT  (Asphaltum,  Mineral  Pitch),  C,  H,  O,  etc. 

3  Struct. — Amorphous  solid  or  very  viscous  liquid;  brittle  to  flexible;  frac- 
ture conchoidal. 

Color  black  to  brownish  black.  Streak  brownish  black.  Luster  pitchy, 
resinous,  dull.  Opaque.  Bituminous  odor;  sticky  when  plastic.  Burns 
with  a  pitchy  odor  and  bright  flame.  (See  p.  212.) 

Massive  deposits  ("pitch  lakes,"  etc.)  and  impregnating  sedimentary 
strata. 

1|    G.  2.0-2.1    SULPHUR  (Brimstone),  S;  traces  of  Te,  Se,  As. 
2£        Struct. — Granular,   fibrous,   compact,   earthy;    reniform,   stalactitic,  in- 
crusting;  orthorhombic  crystals,  pyramidal  (Figs.  34,  35)  or  tabular.     Cleav- 
age indistinct;  brittle;  fracture  conchoidal. 

Color  yellow,  greenish  or  reddish  yellow,  brown,  gray.  Streak  white, 
pale  yellow.  Luster  resinous,  greasy,  adamantine.  Transparent  to  trans- 
lucent. (Seep.  212.) 

In  beds  with  gypsum;  about  vents  of  volcanoes  and  fumaroles;  in  oxi- 
dized parts  of  sulphide  ores;  with  celestite,  gypsum,  calcite,  aragonite. 

2  G.  1.1-1.4    LIGNITE  (Brown  Coal),  C,  H,  O,  etc.;    C  65-76%;    "Fixed" 
2J  C  30-60%. 

Struct. — Compact  amorphous;  woody  structure  common;  fracture  con- 
choidal, splintery;  may  crumble  on  exposure. 

Color  brownish  black  to  black.  Streak  brown  to  brownish  black.  Luster 
dull;  resinous  (jet).  Opaque.  Plant  remains  commonly  recognizable. 
Jet  is  a  black  compact  variety  that  takes  a  polish.  Smoky  yellow  flame.  (See 
p.  212.) 

In  stratified  rocks,  sands,  clays. 

2      G.  1.2-1.5     BITUMINOUS  COAL  (Soft  Coal)  C,  H,  O,  etc.;  C  76-88%;  "Fixed" 
2\  C  48-73%. 

Struct. — Amorphous,  compact,  lamellar,  rarely  fibrous;  brittle;  cubical 
fracture  conspicuous,  sometimes  conchoidal. 

Color  and  streak  black  to  brownish  black.  Luster  pitchy,  vitreous,  dull. 
Opaque.  Burns  with  a  smoky  yellow  flame.  (See  p.  212.) 


SEC.  21]  PHYSICAL  TABLES  129 

H. 

Sometimes  shows  plant  remains;  sometimes  iridescent.  Coking  coal 
becomes  pasty  in  the  fire.  Cannel  coal  is  dull  black,  compact,  structureless, 
with  conchoidal  fracture. 

Beds  in  stratified  rocks,  with  pyrite  and  marcasite. 

2|     G.  5.8-5.9    PYRARGYRITE  (Ruby  Silver,  Dark  Ruby  Silver),  Ag3SbS3; 
3  Ag  59.9%. 

Struct. — Disseminated,  incrusting,  compact;  small  hexagonal-rhombohe- 
dral  crystals  rare.     Cleavage  indistinct;  brittle;  fracture  conchoidal,  uneven. 
Color  dark  red  to  black.     Streak  purplish  red,  cherry-red.   Luster  adaman- 
tine, metallic.     Transparent  to  opaque.     (See  pp.  198,  216.) 
In  veins  with  proustite,  other  silver  minerals,  galena. 

3  G.  4.4-5.1    TETRAHEDRITE  (Gray  Copper),  Cu3SbS3;  often  Fe,  Zn,  Pb, 

4  Ag,  As.     Cu  46.8%;  Ag  3-15%,  Freibergite.     With  increasing 
As  grades  into  Tennantite,  CusAsSs. 

Struct. — Isometric-tetrahedral  crystals  (Figs.  13,  14,  17);  granular,  com- 
pact. Cleavage  none;  brittle;  fracture  uneven. 

Color  steel-gray  to  iron-black.  Streak  dark  gray,  black,  reddish  brown. 
Luster  metallic.  Opaque.  (See  p.  198.) 

Sometimes  coated  with  brass-yellow  chalcopyrite.  In  veins  with  silver 
lead,  and  copper  ores. 

3£    G.5.9-S.2     Descloiziie,  Pb2Zn(OH)VO4;    PbO  55.4%;    ZnO  19.7%;    V2O5 

22.7%. 

Struct. — Small  orthorhombic  crystals  forming  drusy  crusts;  stalactitic, 
compact,  fibrous,  radiated.  Cleavage  none;  brittle;  fracture  small  conchoi- 
dal to  uneven. 

Color  purplish  red  to  brown  and  black;  cuprodescloizite  (containing  5-10% 
Cu)  is  brown,  green,  to  greenish  black.  Streak  orange,  brownish  red,  yellow- 
ish gray.  Luster  greasy.  Transparent  to  opaque.  (See  p.  214.) 

In  veins  with  pyromorphite,  vanadinite,  galena. 

3f  G.  3.8-3.9  SIDERITE  (Spathic  Iron,  Chalybite,  Clay  Ironstone,  Black 
4  Band  Ore)  FeCO3;  Fe  48.3%;  sometimes  Mg,  Mn,  Ca. 

Struct. — Granular,  cleavable,  compact;  hexagonal-rhombohedral  crys- 
tals, curved  and  saddle-shaped  common.  Cleavage  perfect,  three  directions 
at  73°  and  107°  (lOll) ;  brittle;  fracture  uneven. 

Color  gray,  yellow,  brown,  black,  sometimes  white.  Streak  white,  pale 
yellow.  Luster  vitreous,  pearly,  dull.  Translucent  to  opaque.  (See  pp. 
218,  248.) 

In  veins  with  silver  minerals,  pyrite  and  other  sulphides,  cryolite;  beds 
and  concretions  in  limestone,  shale,  and  coal. 

3|     G.  3.9-4.1     SPHALERITE  (Blende,  Zinc  Blende,  Jack,  Black  Jack,  Rosin 

4  Jack),  ZnS;  Zn  67%;  may  be  replaced  by  Fe  up  to  18%. 

Struct. — Cleavable    masses,    granular,    compact,    botryoidal;     rounded 

isometric-tetrahedral  crystals.     Cleavage  pronounced,  six  directions  at  60°, 

90°,  and  120°  (110);  brittle;  fracture  conchoidal. 


130  DETERMINATIVE  MINERALOGY  [SBC.  21 


Color  yellow,  brown,  red,  green,  black;  rarely  white  or  pale  gray  (cleio- 
phane).  Streak  white,  light  to  dark  brown.  Luster  resinous,  adamantine, 
submetaUic.  Transparent  to  opaque.  (See  pp.  200,  228,  250.) 

Ore  deposits  and  veins  with  galena,  pyrite,  chalcopyrite,  fluorite,  barite; 
also  in  limestones. 

3f    G.  3.9-4.0    Wurtztte,  ZnS;  Zn  67%;  S  33%. 

4  Struct. — Small  hemimorphic  hexagonal  crystals,  striated  crosswise; 
fibrous,  incrusting,  compact.  Cleavage  indistinct,  three  directions  at  60° 
and  120°  (lOlO);  brittle;  fracture  uneven,  splintery. 

Color  brownish  black.  Streak  brown.  Luster  resinous.  Translucent 
to  opaque.  (See  pp.  200,  228,  250.) 

In  veins  with  sphalerite,  galena,  quartz,  calcite. 

3|     G.  5.8-6.1     CUPRITE  (Ruby  Copper,  Red  Copper  Ore,  Red  Oxide  of  Copper), 
4  Cu2O;  Cu  88.8%;  with  OH  in  Hydrocuprite. 

Struct. — Compact,  granular,  earthy;  capillary  (chakotrichite) ;  isometric 
crystals.  Cleavage  indistinct;  brittle;  fracture  uneven. 

Color  ruby-red,  reddish  black;  orange  (hydrocuprite) .  Streak  brownish 
red.  Luster  submetaUic,  adamantine,  dull.  Transparent  to  opaque.  (See 
pp.  204,  214.) 

With  native  copper,  malachite,  azurite,  chrysocolla,  limonite,  tenorite, 
chalcocite,  chalcopyrite. 

3£    G.  4.2-4.4    MANGANITB,  MnO-OH;  Mn  62.4%;  H2O  10.3%. 
4          Struct. — Prismatic    orthorhombic    crystals    striated    lengthwise;     often 
groups  or  bundles.     Cleavage  perfect,  one  direction  lengthwise  (010);  rarely 
granular  stalactitic;  brittle;  fracture  uneven. 

Color  steel-gray  to  iron-black.  Streak  reddish  brown  to  black.  Luster 
metallic,  submetaUic.  Opaque.  (See  p.  208.) 

Often  altered  to  pyrolusite.  With  ores  of  manganese  and  iron;  barite, 
calcite,  siderite. 

4  G.  4.4-4.6    XENOTIME,  YP04;  also  Er,  Ce,  Th,  etc. 

5  Struct. — Tetragonal  crystals  (prism,  pyramid);    compact,  disseminated, 
rolled  grains.     Cleavage  distinct,  two  directions  at  90°  (110);   brittle;  frac- 
ture uneven,  splintery. 

Color  yellow,  brown,  red,  pale  gray.  Streak  pale  brown,  yellowish, 
reddish.  Luster  greasy,  vitreous.  Translucent  to  opaque.  (See  p.  256.) 

Like  zircon  but  softer.  In  pegmatite  and  granitic  rocks  with  zircon, 
rutile;  in  sands. 

4i     G.  4.4-5.4     Thorite  (Orangite),  ThSiO4;   some  H2O;   sometimes  U  (Urano- 
5  thorite). 

Struct. — Tetragonal  crystals  (prism,  pyramid);    compact,  disseminated. 
Cleavage  indistinct,  two  directions  at  90°  (110);  brittle;  fracture  conchoidal. 
Color  black,   brown,   orange.     Streak  orange  to   dark  brown.    Luster 
resinous,  greasy.     Transparent  to  translucent.     (See  p.  252.) 

Black  variety  may  inclose  the  orange.  In  pegmatite,  granite,  syenite, 
with  magnetite. 


SEC.  21]  PHYSICAL  TABLES  131 

H. 

5  G.  3.6-4.0  LIMONITE  (Bog  Iron  Ore,  Brown  Hematite,  Broivn  Clay 
5|  Ironstone,  Brown  Ocher,  Yellow  Ocher),  FeO-OH,  with 

capillary  and  adsorbed  water  (compare  Goethite  below). 
Fe  55-60%;  H2O  12-14%. 

Struct. — Amorphous,  earthy,  fibrous,  botryoidal,  stalactitic;  crystals 
pseudomorphous  after  pyrite,  marcasite,  siderite,  etc.  Cleavage  none;  brittle; 
fracture  conchoidal,  splintery,  uneven,  earthy. 

Color  yellow,  brown,  black.     Streak  yellowish  brown.     Luster  metallic, 
silky,  dull;  often  varnish-like  surface.     Opaque.     (See  pp.  204,  208,  218,  250.) 
In  gossan;  replacing  limestone;  nodules  in  clays;  impure  in  bog  iron  ore 
and  earthy  ocher  deposits. 

5      G.  4.0-4.4    GOETHITE  (Lepidocrocite),  FeO-OH;  Fe  62.9%;  H2O  10.1%. 

5£  Struct. — Small  tabular,  scaly  (lepidocrodte) ,  or  acicular  orthorhombic 
crystals;  compact,  granular,  foliated,  fibrous.  Cleavage  distinct,  one  direc- 
tion lengthwise  (010);  brittle;  fracture  uneven,  splintery. 

Color  yellow,  reddish  brown,  dark  brown,  black.  Streak  yellow,  yellowish 
brown.  Luster  submetallic,  adamantine,  dull.  Translucent  to  opaque. 
(See  pp.  204,  208,  218,  250.) 

In  amorphous  and  fibrous  form  the  essential  mineral  of  limonite,  above. 
With  other  iron  ores;  in  cavities  in  hematite  and  limonite;  inclusions  giving 
color  to  some  feldspars  and  quartz. 

5  G.  7.2-7.5  WOLFRAMITE  (Wolfram),  (Fe,Mn)WO4;  grades  into  Ferber- 
5%  ite,  FeWO4,  and  Huebnerite,  MnWO4;  WO3  about  76%. 

Struct. — Thick  tabular,  short  columnar,  and  bladed  monoclinic  crystals, 
resembling  orthorhombic;  cleavable  granular,  and  compact  masses.  Cleavage 
perfect,  one  direction  (010);  brittle;  fracture  uneven.  May  be  slightly 
magnetic. 

Color  dark  gray,  black,  brownish  black,  reddish  brown.  Streak  brownish 
black,  black.  Luster  metallic,  submetallic.  Opaque.  (See  pp.  204,  222,  242.) 

In  veins  in  granite  with  cassiterite,  quartz,  mica,  fluorite,  apatite,  scheelite, 
pyrite,  galena,  sphalerite;  also  in  sands. 

5       G.  4.7-4.9     Hausmannite,  MnMn204;   Mn  72%. 

5§  Struct. — Granular,  compact;  simple  and  twinned  acute  tetragonal  pyra- 
mids, striated  crosswise.  Cleavage  perfect,  one  direction  crosswise  (001); 
brittle;  fracture  uneven. 

Color  black,  brownish  black.  Streak  chestnut-brown.  Luster  submetal- 
lic, greasy.  Opaque.  (See  pp.  208,  250.) 

With  manganese  ores,  magnetite,  hematite,  barite. 

5  G.  2.9-3.4     HORNBLENDE     (an   amphibole),    silicate   of   Ca,    Mg,    Fe, 

6  Al,  etc. 

Struct. — Granular,  columnar,  fibrous,  radiated;  long  prismatic  mono- 
clinic  crystals  (pseudohexagonal)  often  with  rhombohedron-like  terminations; 
prism  angle  124°;  some  prisms  short.  Cleavage  perfect,  two  directions 
lengthwise  at  56°  and  124°  (110);  brittle;  fracture  uneven,  splintery. 


132  DETERMINATIVE  MINERALOGY  [SEC.  21 

II. 

Color  green,  black,  brown,  gray.  Streak  brown,  green,  yellow,  gray, 
white.  Luster  submetallic,  vitreous,  silky,  pearly.  Translucent  to  opaque. 
(See  p.  222,  238.)' 

Common  in  igneous  and  metamorphic  rocks  with  feldspars,  pyroxenes, 
chlorite,  quartz,  calcite. 

5  G.  3.2-3.6    PYROXENE,     Ca(Mg,Fe)(SiO3)2,     ranging     from     Diopside, 

6  CaMg(SiO,)i,  to   Hedenbergite,  CaFe(SiO3)»;    often  some 
Al,  Mn,  and  Na. 

AUGITE  (a  pyroxene),  like  common  pyroxene  above,  with 
A12O3  up  to  15%  or  20%;  sometimes  Na  and  K. 

Struct. — Granular,  columnar,  rarely  fibrous;  lamellar  (diallage) ;  thick 
monoclinic  prisms  four-  or  eight-sided  (Figs.  40,  41).  Cleavage  sometimes 
distinct,  two  directions  lengthwise  at  87°  and  93°  (110);  often  prominent 
parting  crosswise  (001) ;  diallage  has  fine  lamellar  parting  one  direction  length- 
wise (100);  brittle;  fracture  uneven. 

Color  bright  to  dark  green,  grayish  green,  black,  brown.  Streak  greenish, 
brownish,  grayish  to  white.  Luster  vitreous,  submetallic,  dull.  Transparent 
to  opaque.  (See  pp.  220,  222,  240.) 

Common  in  basic  igneous  rocks;  in  crystalline  limestones  with  garnet, 
chlorite,  amphibole,  wollastonite,  magnetite,  pyrite. 

5  G.  3.3-3.5    HYPERSTHENE  (a  pyroxene),  (Fe,Mg)SiOs;  sometimes  Al. 

6  Struct. — Foliated,     cleavable,     granular;     orthorhombic    crystals    rare. 
Cleavage  perfect,  one  direction  (010),  less  distinct  two  directions  (110),  at 
88°,  92°,  and  134°;   brittle;  fracture  uneven. 

Color  grayish,  greenish,  and  brownish  black  to  bronze.  Streak  brownish 
gray,  grayish  white.  Luster  metalloidal  bronzy,  pearly.  Opaque  to  trans- 
lucent. (See  pp.  222,  258.) 

In  basic  igneous  rocks  with  plagioclase  feldspars,  olivine,  amphibole, 
pyroxene,  magnetite,  titanite;  seldom  with  quartz. 

5  G.  4.5-5.0    ILMENITE   (Menaccanite,  Titanic  Iron  Ore),  FeTiO3;  Fe  36.8%. 

6  Ti  31.6%;  sometimes  Mg. 

Struct. — Thin  plates,  granular,  compact,  disseminated;  pebbles,  sand; 
thick  tabular  hexagonal-rhombohedral  crystals.  Cleavage  none;  brittle; 
sometimes  partings;  fracture  conchoidal. 

Color  and  streak  iron  black,  brownish  black.  Luster  metallic,  submetallic. 
Opaque.  May  be  slightly  magnetic.  (See  pp.  206,  210.) 

Disseminated  and  masses  in  igneous  rocks,  gneiss,  schist;  with  hematite, 
apatite,  magnetite,  titanite,  rutile,  quartz.  Common  in  black  sands. 

5  G.  3.7-4.7    PSILOMELANE  (Black  Hematite),  MnO2,  H2O,  BaO,  K2O,  etc. 

6  Struct. — Compact,  botryoidal,  reniform,  stalactitic;   no  crystals.     Cleav- 
age none;  brittle;  fracture  conchoidal,  uneven. 

Color  iron-black,  bluish  black,  steel-gray.  Streak  black,  brownish  black. 
Luster  metallic,  dull.  Opaque.  (See  p.  208.) 

May  have  sooty  coating  of  pyrolusite  or  be  in  layers  with  it.  With  other 
manganese  minerals,  limonite,  barite. 


SEC.  21]  PHYSICAL  TABLES  133 

H. 

5  G.  5.6-5.8    Samarskite,  (Fe,Ca,UO2)3(Ce,Y,Er)2(Cb,Ta)6O21. 

6  Struct. — Compact,  apparently  amorphous,  disseminated;    orthorhombic 
crystals  rare.     Cleavage  none;   brittle;   fracture  conchoidal. 

Color  velvet-black,  black.  Streak  reddish  brown,  grayish  brown.  Luster 
vitreous,  greasy,  submetallic.  Opaque.  (See  pp.  204,  242.) 

Brilliant  luster  and  conchoidal  fracture  often  conspicuous.  In  pegmatite 
with  columbite,  quartz,  mica,  feldspars. 


5£  G.  4.3-4.6  CHROMITE  (Chromic  Iron  Ore),  FeCr2O4;  Cr2O3  68%;  some 
Mg  and  Al. 

Struct. — Disseminated,  granular,  compact;  isometric  crystals  (octa- 
hedrons, Fig.  1)  small  and  rare.  Cleavage  none;  indistinct  parting  four 
directions  at  70|°  and  109?°  (Ill);  brittle;  fracture  conchoidal,  uneven. 

Color  iron-black,  brownish  black.  Streak  dark  brown.  Luster  metallic, 
submetallic,  dull.  Opaque.  May  be  slightly  magnetic.  (See  pp.  208,  210, 
258,  262.) 

In  peridotites  and  serpentine  with  olivine,  enstatite,  talc,  chlorite,  mag- 
netite;%  in  black  sands  and  platinum  placers. 

5$     G.  9.0-9.7    URANINITE  (Pitchblende),  UO3,  UO2,  Pb,  Th,  La,  Y,  He,  Ra,  etc. 

Struct. — Botryoidal,  granular,  lamellar,  compact;  isometric  crystals  rare. 
Cleavage  none;  brittle;  fracture  conchoidal. 

Color  greenish  or  brownish  black,  pitch-black.  Streak  brownish  black, 
grayish  black,  olive-green.  Luster  pitch-like,  submetallic,  dull.  Opaque. 
(See  p.  210.) 

With  ores  of  silver,  lead,  copper,  bismuth;  also  in  pegmatites. 

5|    G.  4.2-4.7    TTJRGITE    (Hydrohematite,    Red  Ocher),   composition  variable; 
6  probably  Goethite,  FeO-OH  and  Hematite,  Fe2O3,  in  solid 

solution,  with  adsorbed  and  capillary  water.     Fe  65-66%; 
H2O  4-6%. 

Struct. — Botryoidal,  stalactitic,  fibrous;  earthy  (red  ocher);  no  crystals 
Cleavage  none;  brittle;  fracture  uneven,  splintery,  earthy. 

Color  red  to  reddish  black.     Streak  dark  red,  reddish  brown.     Luster 
submetallic,  silky,  dull.     Opaque.     (See  pp.  204,  208,  218,  250.) 
Resembles  limonite  in  habit.     With  limonite  and  hematite. 


G.  4.3-5.8    Ferffusonite,  (Y,Er,Ce,U)(Cb,Ta)O4;  some  Ca,  Fe,  H2O. 

Struct. — Disseminated,  compact;  pyramidal  tetragonal  crystals  rare. 
Cleavage  none;  brittle;  fracture  conchoidal,  uneven. 

Color  brownish  black,  brown.  Streak  pale  brown.  Luster  submetallic, 
vitreous;  often  dull  outside.  Translucent,  opaque.  (See  pp.  210,  264.) 

Brilliant  luster  of  fresh  fracture  in  striking  contrast  with  dull  surface.  In 
granite  and  pegmatite  with  quartz,  feldspars,  zircon,  allanite,  gadolinite;  in 
placer  gravels. 


134  DETERMINATIVE  MINERALOGY  [SEC.  21 

H. 

5|     G.  4.9-5.3     HEMATITE  (Red  Iron  Ore,  Specularite,  Specular  Iron,  Kidney 

6|  Ore,  Red  Ocher,  Reddle,  Martile),  FeaOs;  Fe  70%. 

Struct. — Compact,  granular,  radiated,  reniform,  botryoidal,  columnar; 
micaceous  (specular};  earthy  (red  ocher,  reddle);  thin  tabular  hexagonal 
rhombohedral  crystals.  Martite,  octahedral  crystals,  pseudomorphous  after 
magnetite.  Cleavage  none;  brittle;  sometimes  parting;  fracture  uneven, 
splintery. 

Color  steel-gray,  red,  reddish  brown,  black.  Streak  dark  red,  cherry-red, 
brownish  red.  Luster  metallic,  submetallic,  dull.  Opaque.  (See  pp.  204, 
208,  218,  250.) 

Ore  deposits  in  sedimentary  and  metamorphic  rocks;  igneous  contacts. 

5*    G.  5.1-5.2    FRANKLINITE    (Fe,Mn,Zn)(Fe,Mn)2O4;    Fe   39-47%;     Mn 
6£  10-20%;  Zn  5.5-18.5 

Struct. — Compact,    granular,    rounded    disseminated    grains;     isometric 

crystals  (octahedrons,  Fig.  1).     Cleavage  none;  indistinct  octahedral  parting 

(111)  four  directions  at  70^°  and  109|°;  brittle;  fracture  conchoidal,  uneven; 

Color  iron-black.     Streak  black,  brownish  black,  reddish  brown.     Luster 

metallic,  dull.     Opaque.     May  be  slightly  magnetic.     (See  p.  208.) 

In  crystalline  limestone  (New  Jersey)  with  zincite,  willemite,  rhodonite, 
tephroite. 

6      G.  5.3-7.3    CoLUMBn-E,   (Fe,Mn)Cb2O6;  with  Ta,  grading  into   Tantalite, 

(Fe,Mn)Ta2O6;  Ta^  up  to  86%. 

Struct. — Orthorhombic  crystals,  short,  square,  prismatic;  granular,  dis- 
seminated. Cleavage  indistinct,  one  direction  (100);  brittle;  fracture  con- 
choidal, uneven. 

Color  iron-black,  grayish  and  brownish  black;  may  be  iridescent.  Streak 
dark  red,  brownish  black,  black.  Luster  submetallic,  greasy,  dull.  Opaque. 
(See  pp.  204,  210,  242,  264.) 

In  pegmatite  with  beryl,  lepidolite,  tourmaline,  spodumene,  cassiterite. 

6      G.  4.7-4.8     Braunite,  3Mn2O3-MnSiO3;   Mn  64.4%. 

6-|  Struct. — Granular,  drusy  crusts;  minute  tetragonal  crystals,  resembling 
octahedrons.  Cleavage  distinct,  four  directions  at  70°  and  110°  (111); 
brittle;  fracture  uneven. 

Color  brownish  black  to  steel-gray.  Streak  black,  brownish  black. 
Luster  submetallic,  greasy.  Opaque.  (See  p.  208.) 

With  manganese  minerals,  magnetite,  hematite,  barite. 

6  G.  4.1-4.3     RUTILE  (Nigrine),  TiO2;  Ti  60%;  often  Fe. 

7  Struct. — Prismatic  tetragonal  crystals,  striated  lengthwise;    knee-shaped 
and  rosette  twins;    acicular,  compact,  disseminated.     Cleavage  indistinct; 
brittle;  fracture  uneven. 

Color  red,  reddish  brown,  black  (deep  red  when  transparent).  Streak 
white,  gray,  pale  brown.  Luster  metallic,  adamantine.  Transparent  to 
opaque.  (See  pp.  210,  262.) 

In  veins  with  quartz,  feldspars,  hematite,  ilmenite;  hair-like  inclusions  in 
quartz;  in  igneous  contacts  and  metamorphic  rocks. 


SEC.  21,  22]  PHYSICAL  TABLES  135 

H. 

6  G.  6.8-7.1     CASSITERITE  (Tinstone),  SnO2;  Sn  78.6%. 

7  Struct. — Granular,  disseminated;    reniform  with  radiating  fibrous  struc- 
ture (wood  tin);  sand  and  pebbles  (stream  tim);    thick  prismatic  tetragonal 
crystals,  knee-shaped  twins  common  (Fig.  29).     Cleavage  indistinct,  brittle; 
fracture  uneven. 

Color  brown  to  black;  rarely  yellow,  red,  gray,  white.  Streak  white, 
grayish,  brownish.  Luster  adamantine,  greasy,  dull.  Transparent  to  opaque. 
(See  p.  262.) 

In  granite,  gneiss;  with  wolframite,  scheelite,  molybdenite,  tourmaline, 
fluorite,  topaz,  apatite,  lepidolite;  in  pegmatites;  in  sands  and  gravels. 


SECTION  22 

Streak  yellow,  red,  or  brown;  mineral  yellow,  red  or  brown. 

0  G.  3.6-4.0     LIMONITE  (Bog  Iron  Ore,  yellow  Ocher),  FeO-OH  with  capil- 

1  lary  and  adsorbed  water;  Fe  55-60%;  H2O  12-14%.    Yellow,  yellowish 
brown,  earthy.     (See  p.  131.) 

0  G.  4.0-4.4    GOETHITE   (Yellow  Ocher),  FeO-OH;    Fe  62.9%;   H2O  10.1% 

1  Yellow,  yellowish  brown,  earthy.     (See  p.  142.) 

0  G.  4.9-5.0    GREENOCKITE  (Cadmium  Blende),  CdS;  Cd  77.7% 

1  Bright  yellow  powder  on  zinc  ores,  calcite,  etc.     (See  p.  140.) 

0  CARNOTITE,  approx.   (K2,  Ca)O-2U2O3-V2O6-nH2O;   V2O8  20%; 

1  U2O3  63%. 

Dull  opaque  canary  yellow  powder,  minute  waxy  scales;  rarely  solid 
masses;  greasy  feel;  cuts  like  paraffin.  Affects  photographic  plate  in  one  to 
seven  days. 

In  cracks  and  pores  of  sandstone  with  roscoelite  and  other  uranium  and 
vanadium  minerals.  Resembles  beaverite,  below.  (See  p.  228.) 

0  Beaverite,  CuPbFe2(OH)6(SO4)2-H2O. 

1  Dull,  earthy,  friable;  canary-yellow;  microscopic  hexagonal  plates.     (See 
pp.  214,  216.) 

In  oxidized  silver,  lead,  zinc,  and  copper  ores.     Resembles  carnotite. 

0  G.  4.9-5.3    HEMATITE  (Red  Iron  Ore,  Red  Ocher),  FeA;  Fe  70%. 

1  Red  powdery  or  earthy  masses.     (See  p.  134.) 

0  G.  4.2-4.7    TURGITE    (Hydrohematite  Red  Ocher),    hydrous    ferric    oxide; 

1  Fe  65-36%. 

Red  powdery  or  earthy  masses.     (See  p.  144.) 

0  G.  8.0-8.2     CINNABAR  (Natural  Vermilion),  HgS;  Hg  86.2%. 

1  Scarlet  to  cochineal-red  and  brownish  red,  earthy;  heavy.     (See  p.  137.) 


136  DETERMINATIVE  MINERALOGY  [SEC.  22 

H. 

1      G.  5.6-5.7    lodyrite  (lodargyrite),  Agl;  Ag  46%. 

1|  Struct. — Thin  scales,  lamellar,  compact;  hexagonal  prisms.  Cleavage 
conspicuous,  one  direction  crosswise  (0001);  sectile;  thin  flakes  flexible. 

Color  yellow,  yellowish  green,  brownish.  Streak  yellow.  Luster  resin- 
ous, wax-like.  Translucent.  (See  p.  216.) 

In  veins  with  other  silver  minerals,  vanadinite,  descloizite. 

1  G.  0.9-1.0    OZOCERITE  (Mineral  Wax,  Native  Paraffin),  CwH2w+2. 

2  Struct. — Amorphous,  compact,  fibrous,  lamellar;  plastic,  may  be  sticky. 
Color  black,  brownish  black,  brownish  yellow,  leek-green.     Streak  yellow- 
ish brown,   pale  yellow.     Luster  waxy,   greasy,  submetallic.     Translucent, 
sometimes   greenish   opalescence.     (See   p.    212.)     Like   wax,    greasy   feel. 
Burns  with  bright  smoky  flame  and  odor  of  paraffin. 

In  veins  in  sedimentary  rocks. 

1  G.4.5    Molybdite(MolybdicOcher),  Fe2(MoO4)3-7fH20;  MoO3  59.4%. 

2  Struct. — Earthy  powder,   crusts;    rarely  fibrous,   radiating,   or  hair-like 
orthorhombic   crystals.     Cleavage  distinct,   one  direction   crosswise   (001); 
brittle. 

Color  and  streak  straw-yellow,  yellowish  white.  Luster  dull,  silky. 
Translucent  to  opaque.  (See  p.  228.) 

With  molybdenite,  of  which  it  is  an  alteration  product. 

1  G.  1.0-1.8    ASPHALT  (Asphaltum,  Mineral  Pitch),  C,  H,  O,  etc. 

3  Struct. — Amorphous  solid  or  very  viscous  liquid;    fracture  conchoidal; 
brittle  to  flexible  and  plastic. 

Color  black  to  brownish  black.  Streak  brownish  black.  Luster  pitchy, 
resinous,  dull.  Opaque.  Bituminous  odor;  sticky  when  plastic.  Burns, 
with  a  pitchy  odor  and  bright  flame.  (See  p.  212.) 

Massive  deposits  ("  pitch  lakes,"  etc.)  and  impregnating  sedimentary 
strata. 

1J    G.  3.5-3.6    REALGAR,  AsS;  As  70.1%. 

2  Struct. — Granular,    earthy    incrustations,    disseminated;     rarely    short 
monoclinic   prisms,    striated   lengthwise.     Cleavage   distinct,    one   direction 
lengthwise  (010);  slightly  sectile;  fracture  conchoidal. 

Color  deep  red  to  orange,  becoming  yellow  (orpiment)  on  long  exposure 
to  light.  Streak  orange-yellow.  Luster  resinous,  adamantine,  dull.  Trans- 
parent to  translucent  (See  p.  212.) 

In  veins  with  orpiment,  stibnite,  native  arsenic,  pyrite;  disseminated  in 
clay,  dolomite,  etc. 

1J    G.  3.4-3.5    ORPIMENT,  As^;  As  61%. 

2  Struct. — Foliated,  granular,  earthy  incrustations;  rarely  small  mono- 
clinic  crystals.  Cleavage  distinct,  one  direction  (010);  thin  flakes  flexible; 
slightly  sectile. 


SEC.  22]  PHYSICAL  TABLES  137 

H. 

Color  and  streak  lemon-yellow.  Luster  resinous,  greasy;  pearly  on 
cleavage.  Translucent  to  nearly  opaque.  (See  p.  212.) 

In  veins  with  realgar,  stibnite,  barite,  calcite,  pyrite;  forms  from  realgar 
on  long  exposure  to  light. 

1 J     G.  2.0-2.1     SULPHUR  (Brimstone),  8;  traces  of  Te,  Se,  As. 
83        Struct. — Granular,   fibrous,   compact,   earthy;    reniform,   stalactitic,   in- 
crusting;  orthorhombic  crystals,  pyramidal  (Figs.  34,  35)  or  tabular.     Cleav- 
age indistinct;  brittle;  fracture  conchoidal. 

Color  yellow,  greenish  or  reddish  yellow,  brown,  gray.  Streak  white, 
pale  yellow.  Luster  resinous,  greasy,  adamantine.  Transparent  to  trans- 
lucent. (See  p.  212.) 

In  beds  with  gypsum;  about  vents  of  volcanoes  and  fumaroles;  in  oxi- 
dized parts  of  sulphide  ores;  with  celestite,  gypsum,  calcite,  aragonite. 

la     G.  2.9-3.0    ERYTHRITE     (Cobalt     Bloom,     Red     Cobalt,      Cobalt     Ocher), 
2%  Co3(AsO4)2-8H2O;   CoO  37.5%;   sometimes  Ni,  Fe,  Ca. 

Struct. — Minute  acicular  mono  clinic  crystals,  incrusting,  radiating; 
powdery,  earthy.  Cleavage  perfect,  one  direction  lengthwise  (010);  sectile; 
thin  laminae  flexible. 

Color  crimson,  peach-red,  pink;  fades  on  exposure.  Streak  pale  red,  pink. 
Luster  adamantine,  dull.  Transparent  to  opaque.  (See  p.  218.) 

Alteration  product  of  cobalt-arsenic  minerals;  incrusting  cobaltite 
smaltite,  chloanthite,  niccolite. 

1§      G.  2.1    COPIAPITE  (Misy),  Fe4(OH)2(SO4)6-17H2O;  often  AlaiidMg. 
3|        Struct. — Granular,  scales,  crusts,  powder;    six-sided   tabular  monoclinic 
crystals  rare.     Cleavage  one  direction  (010);  brittle;  fracture  uneven,  scaly, 
earthy. 

Color  yellow  to  greenish  and  brownish  yellow.  Streak  yellowish.  Luster 
pearly,  dull.  Translucent  to  opaque.  Disagreeable  metallic  taste.  (See 
p.  218.) 

With  iron  and  copper  sulphates  from  oxidation  of  sulphides. 

2      G.  8.0-8.2     CINNABAR    (Natural    Vermilion,    Mercury    Blende),    HgS; 
2$  Hg  86.2%. 

Struct. — Granular,  earthy,  incrusting;  small  thick  tabular  hexagonal- 
rhombohedral  crystals  rare.  Cleavage  indistinct,  three  directions  at  60°  and 
120°  (1010);  brittle  to  sectile;  fracture  uneven. 

Color  purplish  red  to  brownish  red.  Streak  scarlet  to  brownish  red. 
Luster  adamantine,  dull.  Transparent  to  opaque.  (See  pp.  202,  212.) 

Veins  and  disseminated  hi  sandstone  and  limestone  with  pyrite,  mar- 
casite,  realgar,  stibnite,  barite,  opal,  quartz,  sulphur,  mercury. 

2      G.  5  5-5.6    PROUSTITE  (Ruby  Silver,  Light  Ruby  Silver),  Ag3AsS3;  Ag  65.4%. 
2 \        Struct. — Compact,    disseminated,  incrusting;     small  hexagonal-rhombo- 

hedral  crystals  rare.     Cleavage  three  directions  at  72°  and  108°   (1011),  not 

conspicuous;    brittle;    fracture  conchoidal. 


138  DETERMINATIVE  MINERALOGY  [SBC.  22 

H. 

Color  and  streak  scarlet  to  brownish  red.  Luster  adamantine,  dull. 
Transparent  to  translucent.  (See  pp.  196,  216.) 

In  veins  with  pyrargyrite  and  other  silver  minerals  and  galena. 

2      G.  1.1-1.4    LIGNITE   (Brown  Coal},  C,  H,  O,  etc.;    C  65-76%;  "fixed" 
2i  C  30-60%. 

Struct. — Compact,  amorphous;  woody  structure  common;  fracture  con- 
choidal,  splintery;  may  crumble  on  exposure. 

Color  brownish  black  to  black.  Streak  brown  to  brownish  black.  Luster 
dull;  resinous  (jet).  Opaque.  Plant  remains  commonly  recognizable.  Jet 
is  a  black  compact  variety  that  takes  a  polish.  Smoky  yellow  flame. 
(See  p.  212.) 

In  stratified  rocks,  sands,  clays. 

2      G.  3.1-3.2     Autunite,  Ca(UO2)2(PO4)2-8H20;  U03  62.7%. 
2£        Struct. — Thin  tabular  orthorhombic  (pseudotetragonal)  crystals;  foliated 
and   scaly  micaceous  aggregates.     Cleavage   perfect,   one  direction    (001); 
flakes  brittle. 

Color  lemon  to  sulphur-yellow.  Streak  yellowish.  Luster  pearly,  sub- 
adamantine.  Transparent  to  translucent.  (See  p.  228.) 

With  uraninite  and  other  uranium  minerals;  with  silver,  tin  and  iron  ores. 
Commonly  in  pegmatite. 

2  G.  5.8-6.0     Bromyrite  (Bromargyrite),  AgBr;  Ag  57.4%. 

3  Struct. — Compact,    incrusting,    concretionary;     isometric    crystals   rare. 
Cleavage  none;  sectile;  fracture  uneven. 

Color  bright  yellow  to  amber-yellow,  greenish;  often  grass-green  or  olive- 
green  externally;  little  altered  on  exposure.  Streak  pale  yellow,  greenish 
yellow.  Luster  resinous,  adamantine.  Transparent  to  translucent.  (See 
p.  216.) 

With  cerargyrite,  embolite,  cerusite,  calcite,  in  oxidized  silver  ores. 

2\    G.  9.0    GALA VEEITE,  (Au,Ag)Te2;  Au  38-41%  Ag  2-4%. 

Struct. — Compact;  small  monoclinic  crystals  rare.  Cleavage  none; 
brittle;  fracture  uneven. 

Color  light  bronze-yellow.  Streak  yellowish  gray.  Luster  metallic. 
Opaque.  (See  p.  206.) 

In  veins  with  gold,  sylvanite,  petzite,  tetfahedrite,  pyrite,  fluorite. 

2i    G.  8.8-8.9    COPPER  (Native  Copper),  Cu;  often  some  Ag,  Bi,  Hg,  etc. 
3          Struct. — Scales,  plates,  lumps,  branching  aggregates;    isometric  crystals, 
commonly    distorted.     Cleavage    none;     ductile    and    malleable;     fracture 
hackly. 

Color  copper-red,  tarnish  black,  blue,  green.  Streak  copper-red,  shiny. 
Luster  metallic.  Opaque.  (See  p.  202.) 

In  amygdules  and  veins  in  basic  lavas  and  in  accompanying  conglomerate, 
sandstone,  shale,  etc.,  with  silver,  zeolites,  datolite,  epidote,  quartz,  calcite; 
in  oxidized  zone  of  other  copper  ores. 


SEC.  22]  PHYSICAL  TABLES  139 

H. 

2|     G.  15.6-19.3    GOLD  (Native  Gold),  Au;    commonly  some  Ag,  sometimes 

3  Cu,  Bi,  etc.;  Ag  20%  or  more,  Electrum. 

Struct. — Grains,  scales,  lumps;  rarely  small  isometric  crystals,  commonly 
distorted.  Cleavage  none;  ductile  and  malleable;  fracture  hackly. 

Color  gold-yellow,  brass-yellow,  pale  yellow;  does  not  tarnish.  Streak 
gold-yellow,  shiny.  Luster  metallic.  Opaque.  (See  p.  202.) 

In  veins  with  quartz,  pyrite,  galena,  sphalerite,  and  other  sulphides; 
in  sands  and  gravels  (placers). 

2i    G.  5.8-5.9    PYRARGYRITE  (Ruby  Silver,  Dark  Ruby  Silver'),  Ag3SbS3; 
3  Ag  59.9%.:  some  As. 

Struct. — Disseminated,  incrusting,  compact;  small  hexagonal-rhombohedral 
crystals  rare.  Cleavage  indistinct;  brittle;  fracture  conchoidal,  uneven. 

Color  dark  red  to  black.     Streak  purplish  red,  cherry-red.    Luster  ada- 
mantine, metallic.     Transparent  to  opaque.     (See  pp.  198,  216.) 
In  veins  with  proustite,  other  silver  minerals,  galena. 

2|     G.  5.9-6.1     CROCOITE,  PbCrO4;  Pb  63.9%. 

3          Struct. — Monoclinic   prismatic   crystals;    acicular,    granular,    columnar, 

incrusting.     Cleavage  distinct,  two  directions  at  86°  and  104°   (110),  less 

distinct  two  other  directions  (100)  (001);  sectile;  fracture  conchoidal,  uneven. 

Color  bright  red.     Streak  orange-yellow.     Luster  adamantine,  vitreous. 

Translucent.     (See   p.    214.) 

In  veins  with  galena,  quartz,  pyrite,  vanadinite,  wulfenite. 

2^     G.  2.7-2.8     Polyhdite,  K2MgCa2(SO4)42H2O;  K2O  15.6%. 
3          Struct. — Fibrous,  lamellar,  compact;   monoclinic  (?).     Cleavage  distinct, 
one  direction;  brittle;  fracture  splintery. 

Color  flesh-  to  brick-red;  yellowish  red  to  white.     Streak  white,  reddish 
to  yellowish  white.    Luster  greasy,  pearly.    Translucent  to  opaque.     Taste 
weakly  bitter  and  astringent.     (See  p.  226.) 
In  beds  of  salt,  gypsum,  and  clay. 

3      G.  6.6-7.2    VANADINITE,  Pb6Cl(VO4)3;    Pb  73%;    V2O6  19.4%;  sometimes 

P  and  As. 

Struct. — Small  hexagonal  crystals  (prisms,  Fig.  49),  sometimes  hollow; 
fibrous,  incrusting,  compact,  globular.  Cleavage  none;  brittle;  fracture 
uneven,  conchoidal. 

Color  ruby-red,  brown,  yellow.  Streak  white,  pale  yellow.  Luster 
resinous  on  fracture.  Translucent  to  opaque.  (See  p.  214.) 

In  oxidized  parts  of  lead  ores;  in  gold  and  silver  veins;  with  pyromorphite, 
wulfenite,  galena. 

3      G.  4.1^.6    Olivenite  (Wood  Copper),  Cu2(OH)AsO4;   Cu  49.8%; 

AsaOs  40.7%. 

Struct. — Fibrous,  velvety  crusts,  reniform,  granular,  earthy;  prismatic 
and  acicular  orthorhombic  crystals.  Cleavage  none;  brittle;  fracture  con- 
choidal, uneven. 


140  DETERMINATIVE  MINERALOGY  [SEC.  22 

H. 

Color  olive  to  blackish  green,  brown,  straw-yellow,  grayish  white.  Streak 
olive-green,  brown.  Luster  adamantine,  vitreous.  Transparent  to  opaque. 
(See  p.  216.) 

In  the  oxidized  zone  with  copper  minerals. 

3  G.  4.9-5.0    GREENOCKITE  (Cadmium  Blende),  CdS;  Cd  77.7%. 

3f  Struct. — Earthy  coatings,  powdery;  rarely  small  hexagonal  crystals. 
Cleavage  inconspicuous,  three  directions  at  60°  and  120°  (1120);  brittle; 
fracture  conchoidal. 

Color    yellow,    orange-yellow,    greenish   yellow.     Streak   orange-yellow. 
Luster  resinous,  adamantine,  dull.     Translucent  to  opaque.     (See  p.  250.) 
With  sphalerite,  smithsonite,  galena,  calcite. 

3£    G.  5.9-6.2     Desdmzite,    Pb2Zn(OH)VO4;     PbO  55.4%;     ZnO  19.7%; 

V208  22.7%. 

Struct. — Small  orthorhombic  crystals  forming  drusy  crusts;  stalactitic, 
compact,  fibrous,  radiated.  Cleavage  none;  brittle;  fracture  small  con- 
choidal to  uneven. 

Color   purplish   red   to   brown   and   black;     cuprodescloizite    (containing 
5-10%  Cu)  is  brown,  green,  to  greenish  black.      Streak  orange,   brownish 
red,  yellowish  gray.    Luster  greasy.     Transparent  to  opaque.     (See  p.  214.) 
In  veins  with  pyromorphite,  vanadinite,  galena. 

3|     G.  3.8-3.9     SIDERITE    (Spathic   Iron,    Chalybite,    Clay   Ironstone,    Black 

4  Band  Ore),  FeCO3;  Fe  48.3%;  sometimes  Mg,  Mn,  Ca. 
Struct. — Granular,  cleavable,  compact;  hexagonal-rhombohedral  crystals, 

curved  and  saddle-shaped  common.  Cleavage  perfect,  three  directions  at 
73°  and  107°  (1011);  brittle;  fracture  uneven. 

Color  gray,  yellow,  brown,  black,  sometimes  white.  Streak  white,  pale 
yellow.  Luster  vitreous,  pearly,  dull.  Translucent  to  opaque.  (See  pp. 
218,  248.) 

In  veins  with  silver  minerals,  pyrite  and  other  sulphides,  cryolite;  beds 
and  concretions  in  limestone,  shale,  and  coal. 

3*  G.  3.9-4.1  SPHALERITE  (Blende,  Zinc  Blende,  Jack,  Black  Jack,  Rosin 
4  Jack),  ZnS;  Zn  67%;  may  be  replaced  by  Fe  up  to  18%. 

Struct. — Cleavable  masses,  granular,  compact,  botryoidal;  rounded 
isometric-tetrahedral  crystals.  Cleavage  pronounced,  six  directions  at  60°, 
90°,  and  120°  (110);  brittle;  fracture  conchoidal. 

Color  yellow,  brown,  red,  green,  black;  rarely  white  or  pale  gray  (cleio- 
phane).  Streak  white,  light  to  dark  brown.  Luster  resinous,  adamantine, 
submetallic.  Transparent  to  opaque.  (See  pp.  200,  228,  250.) 

Ore  deposits  and  veins  with  galena,  pyrite,  chalcopyrite,  fluorite,  barite; 
also  in  limestones. 

3|    G.  3.9-4.0    Wurtzite,  ZnS;  Zn67%;  S33%. 

4          Struct. — Small    hemimorphic    hexagonal    crystals,    striated    crosswise; 

fibrous,  incrusting,   compact.     Cleavage  indistinct,  three  directions  at  60° 

and  120°  (1010);   brittle;   fracture  uneven,  splintery. 


SEC.  22]  PHYSICAL  TABLES  141 

H. 

Color  brownish  black.  Streak  brown.  Luster  resinous.  Translucent 
to  opaque.  (See  pp.  200,  228,  250.) 

In  veins  with  sphalerite,  galena,  quartz,  calcite. 

3£  G.  5.8-6.1  CUPRITE  (Ruby  Copper,  Red  Copper  Ore,  Red  Oxide  of  Copper), 
4  Cu2O;  Cu  88.8%;  with  OH  in  Hydrocuprite. 

Struct. — Compact,  granular,  earthy,  capillary  (chalcotrichite);  isometric 
crystals.  Cleavage  indistinct;  brittle;  fracture  uneven. 

Color  ruby-red,  reddish  black;  orange  (hydrocuprite) .  Streak  brownish 
red.  Luster  submetallic,  adamantine,  dull.  Transparent  to  opaque. 

With  native  copper,  malachite,  azurite,  chrysocolla,  limonite,  tenorite, 
chalcocite,  chalcopyrite.  (See  pp.  204,  214.) 

3*  G.  6.5-7.1  PYROMORPHITE  (Green  Lead  Ore),  Pb6Cl(P04)3;  Pb  76.3%; 
4  P2O6  15.7%. 

Struct. — Small  prismatic  hexagonal  crystals,  often  rounded,  barrel- 
shaped,  sometimes  hollow;  incrusting,  reniform,  disseminated.  Cleavage 
none;  brittle;  fracture  «onchoidal,  uneven. 

Color  green,  yellow,  brown,  white,  gray.  Streak  pale  yellow,  greenish 
yellow,  white.  Luster  resinous,  greasy,  adamantine.  Translucent  to  opaque. 
(See  p.  214.) 

In  oxidized  parts  of  lead  veins  with  galena,  cerusite,  mimetite,  barite, 
limonite. 

4      G.  5.4-5.7    ZINCITE  (Red  Zinc  Ore),  ZnO;   Zn  80.3%;   commonly  Mn. 
4 5         Struct. — Lamellar,    granular;     rarely    hemimorphic    hexagonal    crystals. 
Cleavage  distinct,  one  direction  (0001);  brittle;  fracture  uneven. 

Color  deep  red  to  orange.  Streak  orange-yellow.  Luster  adamantine. 
Translucent  to  opaque.  (See  p.  250.) 

In  crystalline  limestone  with  franklinite,  willemite,  rhodonite. 

4  G.  4.4-4.6    XENOTIME,  YPO4;  also  Er,  Ce,  Th,  etc. 

5  Struct. — Tetragonal  crystals  •  (prism,  pyramid);    compact,  disseminated, 
rolled  grains.     Cleavage  distinct,  two  directions  at  90°  (110);  brittle;  fracture 
uneven,  splintery. 

Color  yellow,  brown,  red,  pale  gray.  Streak  pale  brown,  yellowish,  red- 
dish. Luster  greasy,  vitreous.  Translucent  to  opaque.  (See  p.  256.) 

Like  zircon  but  softer.  In  pegmatite  and  granitic  rocks  with  zircon, 
rutile;  in  sands. 

4i    G.  5.9-6.2    SCHEELITE,  CaWO4;    WO3  80.6%;    some  Mo;    sometimes  Cu 

5  (Cuproscheelite) . 

Struct. — Small  pyramidal  tetragonal  crystals,  resembling  octahedrons, 
sometimes  tabular;  incrusting,  granular,  compact;  Cleavage  inconspicuous, 
four  directions  at  80°,  110°,  and  130£°  (111);  brittle;  fracture  conchoidal, 


142  DETERMINATIVE  MINERALOGY  [Sec.  22 

H. 

Color  white,  yellow,  brownish,  greenish,  reddish.  Streak  white  to  yellow- 
ish. Luster  greasy,  adamantine.  Transparent  to  translucent.  (See  pp. 
234,  254,  258.) 

In  veins  and  contacts  with  quartz,  cassiterite,  topaz,  fluorite,  apatite, 
molybdenite. 

4£    G.  4.4-5.4     Thorite  (Orangite),  ThSiO4;  some  H2O;  sometimes  U  (Urano- 
5  thorite). 

Struct. — Tetragonal  crystals  (prism,  pyramid);    compact,  disseminated. 
Cleavage  indistinct,  two  directions  at  90°  (110);  brittle;  fracture  conchoidal. 
Color  black,   brown,   orange.     Streak  orange  to   dark  brown.    Luster 
resinous,  greasy.     Transparent  to  translucent.     (See  p.  252.) 

Black  variety  may  inclose  the  orange.  In  pegmatite,  granite,  syenite, 
with  magnetite. 

5      G.  3.6-4.0    LIMONITE   (Bog   Iron  Ore,   Brown    Hematite,   Brown  Clay 
5\  Ironstone,  Brown  Ocher,  yellow  Ocher),  FeO-OH  with  capil- 

lary   and    adsorbed    water    (compare    Goethite,   below); 
Fe  55-60%;  H2O  12-14%. 

Struct. — Amorphous,  earthy,  fibrous,  botryoidal,  stalactitic;  crystals 
pseudomorphous  after  pyrite,  marcasite,  siderite,  etc.  Cleavage  none; 
brittle;  fracture  conchoidal,  splintery,  uneven,  earthy. 

Color  yellow,  brown,  black.     Streak  yellowish  brown.     Luster  metallic, 
silky,  dull;  often  varnish-like  surface.    Opaque.     (See  pp.  204,  208,  218,  250.) 
In  gossan;   replacing  limestone;  nodules  in  clays;  impure  in  bog  iron  ore 
and  earthy  ocher  deposits, 

5      G.  4.0-4.4    GOETHITE  (Lepidocrosite),  FeO- OH;  Fe  62.9%;  H2O  10.1%. 

5|  Su-act. — Small  tabular,  scaly  (lepidocrosite),  or  acicular  orthorhombic 
crystals;  compact,  granular,  foliated,  fibrous.  Cleavage  distinct,  one  direc- 
tion lengthwise  (010);  brittle;  fracture  uneven,  splintery. 

Color  yellow,  reddish  brown,  dark  brown,  black.  Streak  yellow,  yellowish 
brown.  Luster  submetallic,  adamantine,  dull.  Translucent  to  opaque. 
(See  pp.  204,  208,  218,  250.) 

In  amorphous  and  fibrous  form  the  essential  mineral  of  limonite,  above. 
With  other  iron  ores;  in  cavities  in  hematite  and  limonite;  inclusions  giving 
color  to  some  feldspars  and  quartz, 

5      G.  7.2-7.5    WOLFRAMITE    (Wolfram),    (Fe,Mn)W04;   grades  into   Fer- 

5i  berite,  FeWO4)  and  Huebnerite,  MnWO4;   WO3  about  76%. 

Struct. — Thick  tabular,  short  columnar,  and  bladed  monoclinic  crystals, 

resembling  orthorhombic;    cleavable,  granular,  compact.     Cleavage  perfect, 

one  direction  (010);   brittle;   fracture  uneven.     May  be  slightly  magnetic. 

Color  dark  gray,  black,  brownish  black,  reddish  brown.     Streak  brownish 
black,  black.     Luster  metallic,  submetallic.    Opaque.    (See  pp.  204,  222,  242.) 
In  veins  in  granite  with  cassiterite,  quartz,  mica,  fluorite,  apatite,  scheelite, 
pyrite,  galena,  sphalerite;  also  in  sands. 


SEC.  22]  PHYSICAL  TABLES  143 

H. 

5      G.  7.3-7.7    NICCOLITE  (Copper  Nickel),  NiAs;    Ni  43.9%;  some  Fe,  Co, 

5}  Sb,  S. 

Struct. — Compact,  disseminated;  small  hexagonal  crystals  rare.  Cleav- 
age none;  brittle;  fracture  uneven. 

Color  light  copper-red,  tarnish  gray  to  blackish.  Streak  brownish  black. 
Luster  metallic.  Opaque.  (See  p.  196.) 

May  have  coating  of  green  (annabergite) .  With  cobalt,  nickel,  and 
silver  minerals,  bismuth,  arsenic,  calcite. 

5      G.  4.7-4.9     Hausmannite,  MnMn2O4;  Mn  72%. 

5?  Struct. — Granular,  compact;  simple  and  twinned  acute  tetragonal  pyra- 
mids, striated  crosswise.  Cleavage  perfect,  one  direction  crosswise  (001); 
brittle;  fracture  uneven. 

Color  black,  brownish  black.  Streak  chestnut-brown.  Luster  sub- 
metallic,  greasy.  Opaque.  (See  pp.  208,  250.) 

With  manganese  ores,  magnetite,  hematite^  barite. 

5  G.  2.9-3.4     HORNBLENDE  (an  amphibole),  silicate  of  Ca,  Mg,  Fe,  Al,  etc. 

6  Struct. — Granular,    columnar,   fibrous,   radiated;    long  prismatic  mono- 
clinic   crystals   (pseudohexagonal),   often  with  rhombohedron-like  termina- 
tions;   prism  angle  124°;    some  prisms  short.     Cleavage  perfect,  two  direc- 
tions lengthwise  at  56°  and  124°  (110);  brittle;  fracture  uneven,  splintery. 

Color  green,  black,  brown,  gray.  Streak  brown,  green,  yellow,  gray, 
white.  Luster  submetallic,  vitreous,  silky,  pearly.  Translucent  to  opaque. 
(See  pp.  222,  238.) 

Common  in  igneous  and  metamorphic  rocks  with  feldspars,  pyroxenes, 
chlorite,  quartz,  calcite. 

5  G.  3.2-3.6    PYROXENE,     Ca(Mg,Fe)(SiO3)2,     ranging     from     Diopside, 

6  CaMg(SiO3)2,   to    Hedenbergite,   CaFe(SiO3)2;    often  some 
Al,  Mn,  and  Na. 

AUGITE  (a  pyroxene),  like  common  pyroxene  above,  with 
A12O3  up  to  15%  or  20%;  sometimes  Na  and  K. 

Struct. — Granular,  columnar,  rarely  fibrous;  lamellar  (diallage);  thick 
monoclinic  prisms  four-  or  eight-sided  (Figs.  40,  41).  Cleavage  sometimes 
distinct,  two  directions  lengthwise  at  87°  and  93°  (110);  often  prominent 
parting  crosswise  (001);  diallage  has  fine  lamellar  parting  one  direction 
lengthwise  (100);  brittle;  fracture  uneven. 

Color  bright  to  dark  green,  grayish  green,  black,  brown.  Streak  greenish, 
brownish,  grayish  to  white.  Luster  vitreous,  submetallic,  dull.  Trans- 
parent to  opaque.  (See  pp.  220,  222,  240.) 

Common  in  basic  igneous  rocks;  in  crystalline  limestones  with  garnet, 
chlorite,  amphibole,  wollastonite,  magnetite,  pyrite. 

5  G.  3.3-3.5    HYPERSTHENE  (a  pyroxene),  (Fe,Mg)SiO3;  sometimes  Al. 

6  Struct. — Foliated,     cleavable,     granular;      orthorhombic     crystals    rare. 
Cleavage  perfect,  one  direction  (010),  less  distinct  in  two  directions  (110), 
431°,  88°,  and  92°;  brittle;   fracture  uneven. 


144  DETERMINATIVE  MINERALOGY  [SEC.  22 


Color  grayish,  greenish,  and  brownish  black  to  bronze.  Streak  brownish 
gray,  grayish  white.  Luster  metalloidal,  bronzy,  pearly.  Opaque  to  trans- 
lucent. (See  pp.  222,  258.) 

In  basic  igneous  rocks  with  plagioclase  feldspars,  olivine,  amphibole, 
pyroxene,  magnetite,  titanite;  seldom  with  quartz. 

5i  G.  4.3-4.6  CHROMITE  (Chromic  Iron  Ore),  FeCr2O4;  Cr2O3  68%;  some 
Mg  and  Al. 

Struct. — Disseminated,  granular,  compact;  isometric  crystals  (octahe- 
drons, Fig.  1)  small  and  rare.  Cleavage  none;  indistinct  parting  four  direc- 
tions at  70^°  and  109J°  (111);  brittle;  fracture  conchoidal,  uneven. 

Color  iron-black,  brownish  black.  Streak  dark  brown.  Luster  metallic, 
submetallic,  dull.  Opaque.  May  be  slightly  magnetic.  (See  pp.  208,  210, 
258,  262.) 

In  peridotites  and  serpentine;  with  olivine,  enstatite,  talc,  chlorite,  mag- 
netite; in  black  sands  and  platinum  placers. 

5£     G.  4.3-5.8    Fergusonite,  (Y,Er,Ce,U)(Cb,Ta)O4;  some  Ca,  Fe,  H2O. 
6         Struct. — Disseminated,    compact;     pyramidal    tetragonal    crystals   rare. 
Cleavage  none;   brittle;  fracture  conchoidal,  uneven. 

Color  brownish  black,  brown.  Streak  pale  brown.  Luster  submetallic, 
vitreous;  often  dull  outside.  Translucent,  opaque.  (See  pp.  210,  264.) 

Brilliant  luster  of  fresh  fracture  in  striking  contrast  with  dull  surface. 
In  granite  and  pegmatite  with  quartz,  feldspars,  zircon,  allanite,  gadolinite; 
in  placer  gravels. 

5|     G.  4.2-4.7     TURGITE    (Hydrohematite,    Red   Ocher),  composition   variable; 
6  probably  Goethite,  FeO-OH,  and   Hematite,  Fe^Gs,  in  solid 

solution,  with  adsorbed  and  capillary  water.     Fe  65-66%; 
H2O4-6% 

Struct. — Botryoidal,  stalactitic,  fibrous,  earthy  (red  ocher);  no  crystals 
Cleavage  none;  brittle;  fracture  uneven,  splintery,  earthy. 

Color  red  to  blackish  red.     Streak  dark  red,  reddish  brown.     Luster  sub- 
metallic,  silky,  dull.     Opaque.     (See  pp.  204,  208,  218,  250.) 
Resembles  limonite  in  habit.     With  limonite  and  hematite. 

5i     G.  4.9-5.3     HEMATITE  (Red  Iron  Ore,  Speculariie,  Specular  Iron,  Kidney 
6|  Ore,  Red  Ocher,  Reddle,  Martile),  Fe-A;  Fe  70%. 

Struct. — Compact,  granular,  radiated,  reniform,  botryoidal,  columnar; 
micaceous  (specular) ;  earthy  (red  ocher,  reddle) ;  thin  tabular  hexagonal- 
rhombohedral  crystals.  Martite,  octahedral  crystals,  pseudomorphous  after 
magnetite.  Cleavage  none;  sometimes  parting;  brittle;  fracture  uneven, 
splintery. 

Color  steel-gray,  red,  reddish  brown,  black.  Streak  dark  red,  cherry-red, 
brownish  red.  Luster  metallic,  submetallic,  dull.  Opaque.  (See  pp.  204, 
208,  218,  250.) 

Ore  deposits  in  sedimentary  and  metamorphic  rocks;  igneous  contacts. 


SEC.  22,  23]  PHYSICAL  TABLES  145 

H. 

6  G.  4.1-4.3    RUTILE  (Nigrine),  TiO2;  Ti  60%;  often  Fe. 

7  Struct. — Prismatic  tetragonal  crystals,  .striated  lengthwise;    knee-shaped 
and  rosette  twins;    acicular,   compact,  disseminated.     Cleavage  indistinct; 
brittle;  fracture  uneven. 

Color  red,  reddish  brown,  black  (deep  red  when  transparent).  Streak 
white,  gray,  pale  brown.  Luster  metallic,  adamantine.  Transparent  to 
opaque.  (See  pp.  210,  262.) 

In  veins  with  quartz,  feldspars,  hematite,  ilmenite;  hair-like  inclusions 
in  quartz;  in  igneous  contacts  and  metamorphic  rocks 

6  G.  6.8-7.1    CASSITERITE  (Tinstone),  Sn02;  Sn  78.6%. 

7  Struct. — Granular,  disseminated;    reniform  with  radiating  fibrous  struc- 
ture (wood  tin);    sand  and  pebbles  (stream  tin);    thick  prismatic  tetragonal 
crystals,  knee-shaped  twins  common  (Fig.  29).     Cleavage  indistinct;  brittle; 
fracture  uneven. 

Color  brown  to  black;  rarely  yellow,  red,  gray,  white.  Streak  white, 
grayish,  brownish.  Luster  adamantine,  greasy,  dull.  Transparent  to  opaque. 
(See  p.  262.) 

In  granite,  gneiss;  with  wolframite,  scheelite,  molybdenite,  tourmaline, 
fluorite,  topaz,  apatite,  lepidolite;  in  pegmatites;  in  sands  and  gravels. 


SECTION  23 

Streak  blue  or  green. 

1  G.  3.2-3.3    BLUE  ASBESTOS  (Crocidolite),  approx.  NaFe"Fe"'  (SiO3)3. 

2  Struct. — Long  delicate  flexible  fibers,  easily  separable. 
Color  and  streak  lavender-blue.     (See  p.  148.) 

1  G.  2.2-2.4    GLAUCONITE  (Greensand,  Green  Earth),  approx.  KFe(Si03)2 •  H2O; 

2  K206-9%;  some  Al  and  Mg. 

Struct. — Granular,  earthy,  disseminated;  amorphous.  Cleavage  none; 
brittle;  fracture  earthy,  uneven. 

Color  yellowish  green,  grayish  green,  blackish  green.  Streak  light  green, 
greenish  white.  Luster  vitreous,  dull.  Opaque.  (See  p.  220.) 

Abundant  in  greensand  beds  (so-called  marls);  disseminated  in  sands, 
clays,  sandstones,  limestones. 

1      G.  2.6-3.0    CHLORITE  (Clinochlore,  Pennine,  Prochloriie),  H,  Fe,  Mg,  Al 
3 1  silicates. 

Struct. — Foliated,  scaly,  granular,  compact,  earthy;  tabular  six-sided 
monoclinic  crystals  rare.  Cleavage  perfect,  one  direction  (001);  thin  flakes 
flexible,  tough,  not  elastic;  fracture  scaly,  earthy;  slight  soapy  feel. 

Color  light  to  dark  green.  Streak  white,  greenish  white,  grayish.  Luster 
pearly,  vitreous,  dull.  Translucent  to  opaque.  (See  pp.  236,  254.) 

In  schists,  greenstones,  green  slates,  serpentines,  peridotites;  with  mag- 
netite, chromite,  garnet,  talc,  pyroxene,  serpentine,  corundum. 


146  DETERMINATIVE  MINERALOGY  [SEC.  23 

H. 

1      G.  3.0-3.1    ANNABERGITE    (Nickel   Bloom,    Nickel    Ocher,    Nickel  Green), 

2\  Ni3(AsO4)2-8H2O;   Ni  29.4%;  sometimes  Co  and  Ca. 

Struct. — Earthy,  incrusting,  compact,  stains;  capillary  monoclinic  crys- 
tals rare.  Cleavage  none;  brittle;  fracture  uneven. 

Color  apple-green,  light  green.  Streak  pale  green,  greenish  white.  Luster 
dull,  vitreous.  Opaque  to  translucent.  (See  p.  218.) 

Oxidation  product  of  nickel  arsenides;  with  smaltite,  niccolite,  chloanthite, 
calcite. 

1  G.  2.3-2.8    GARNIERITE  (Nowneite,  Genthite),  approx.  H2(Ni,Mg)SiO4 •  nH2O ; 
4  Ni  8-35%. 

Struct. — Compact,  botryoidal,  incrusting,  earthy.  Cleavage  none; 
brittle;  fracture  conchoidal,  earthy.  Sometimes  greasy  feel. 

Color  pale  yellowish  green  to  emerald-green.  Streak  white,  greenish 
white.  Luster  greasy,  resinous,  dull.  Opaque.  (See  pp.  254,  258.) 

Veins  in  peridotites,  serpentine;  with  chromite,  talc,  chlorite. 

1|     G.  2.6-2.7    VIVIANITE  (Blue  Iron  Earth),  Fe3(PO4)2-8H2O;  P2O6  28.3%. 

2  Struct. — Radial  fibrous,  earthy;    prismatic  and  tabular  monoclinic  crys- 
tals.    Cleavage  distinct,   one  direction   (010);    sectile;    fracture  splintery, 
earthy;  thin  flakes  flexible. 

Color  blue,  green,  greenish  black;  colorless  when  fresh.  Streak  white, 
blue,  greenish-blue.  Luster  pearly  on  cleavage;  vitreous,  dull.  Transpar- 
ent to  opaque.  (See  p.  218.) 

In  clay,  marl,  peat;  in  cavities  of  fossils;  with  limonite;  in  veins  with 
pyrrhotite,  pyrite,  gold. 

2      G.  2.9-3.0    ROSCOELITE     (Vanadium    Mica),    approx.   H2K(Al,V)3(SiO4)3; 

V2O3  20-29%;  some  Mg,  Fe. 
Struct. — Minute  micaceous  scales. 

Color  dark  green  to  brown.    Luster  pearly.     Translucent.     (See  p.  236.) 
In  veins  with  quartz,  gold,  and  tellurium;  disseminated  in  sandstone  with 
carnotite. 

2  G.  2.0-2.2    CHRYSOCOLLA,  approx.  CuSi03-2H2O;   variable;  Cu  20-50%. 

3  Struct. — Amorphous,     compact,     reniform,     incrusting,     stains,     earthy. 
Cleavage  none;  brittle;  fracture  conchoidal. 

Color  green,  greenish  blue,  blue;  brown  to  black  from  impurities.  Streak 
white  to  pale  blue  or  green.  Luster  vitreous,  greasy,  dull.  Translucent  to 
opaque.  (See  p.  254.) 

In  oxidized  parts  of  copper  deposits,  with  malachite,  azurite,  cuprite, 
native  copper. 

3      G.  4.1-4.6    Olioenite  (Wood  Copper),  Cu2(OH)As04;  Cu  49.8%;  AssOs  40.7% 
Struct. — Fibrous,  velvety  crusts,  reniform,  granular,  earthy;    prismatic 
and  acicular  orthorhombic  crystals.     Cleavage  none;    brittle;    fracture  con- 
choidal, uneven. 


SEC.  23]  PHYSICAL  TABLES  147 

H. 

Color  olive  to  blackish  green,  brown,  straw-yellow,  grayish  white.  Streak 
olive-green,  brown.  Luster  adamantine,  vitreous.  Transparent  to  opaque. 
(See  p.  216.) 

In  the  oxidized  zone  with  copper  minerals. 

3      G.  2.6-2.7    Zaratite     (Emerald     Nickel,     Texasite),     Ni3(OH)4CO3-4H2O; 

Ni  46.8%. 

Struct. — Incrusting,  mammillary,  minutely  crystalline,  compact.  Cleav- 
age none;  brittle;  fracture  smooth. 

Color  emerald-green.  Streak  green.  Luster  vitreous.  Transparent  to 
translucent.  (See  p.  248.) 

In  peridotite  and  serpentine  with  chromite;  in  nickeliferous  magnetite. 

3  G.  3.7-3.8    ATACAMITE,  Cu2(OH)3Cl;  Cu  59.5%;  Cl  16.6%;  H2O  12.7%. 
3£        Struct. — Crystalline   aggregates,    fibrous,    granular,    incrusting;     slender 

prismatic  orthorhombic  crystals,  striated  lengthwise.  Cleavage  distinct, 
one  direction  lengthwise  (010) ;  brittle;  fracture  conchoidal. 

Color  emerald-green,  blackish  green.  Streak  apple-green.  Luster  vitre- 
ous, adamantine.  Transparent  to  opaque.  (See  p.  214.) 

With  malachite  and  other  secondary  copper  minerals,  also  sulphides, 
limonite,  hematite. 

3£    G.  3.9-4.0     MALACHITE    (Green   Copper,   Green   Carbonate   of  Copper), 

4  Cu2(OH)2CO3;  Cu  57.4%. 

Struct. — Radial  fibrous,  botryoidal,  stalactitic,  incrusting,  earthy;  slender 
monoclinic  crystals  in  tufts.  Cleavage  one  direction  crosswise  (001);  brittle; 
fracture  conchoidal,  splintery. 

Color  emerald-green,  grass-green,  dark  green.  Streak  light  green.  Luster 
adamantine,  silky,  dull.  Translucent  to  opaque.  (See  p.  214.) 

With  other  oxidized  copper  minerals,  sulphides,  native  copper. 

3£     G.  3.7-3.8    AZURITE  (Chessylite,  Blue  Copper,  Blue  Carbonate  of  Copper), 
4  CU3(OH)2(CO3)2;   Cu  55.2%. 

Struct. — Short  prismatic  or  tabular  monoclinic  crystals;  radiating, 
botryoidal,  incrusting,  earthy.  Cleavage  distinct,  two  directions  at  121° 
(021);  brittle;  fracture  conchoidal. 

Color  azure-blue,  dark  blue.  Streak  blue.  Luster  vitreous,  dull.  Trans- 
lucent to  opaque.  (See  p.  214.) 

With  other  oxidized  copper  minerals,  sulphides,  native  copper. 

3|    G.  3.9    BROCHANTITE,  Cu^OH^CU;  Cu  56.2%. 

4  Struct. —  Slender  prismatic  orthorhombic  crystals,  striated  lengthwise; 
drusy  crusts,  fibrous,  massive,  reniform.  (Waringtonile,  nonstriated  doubly 
curving  wedge-shaped  crystals;  sp.  g.  3.4-3.5).  Cleavage  distinct,  one  direc- 
tion lengthwise  (010);  brittle;  fracture  uneven. 

Color  emerald-green,  blackish  green.  Streak  light  green.  Luster  vitre- 
ous, pearly.  Transparent  to  translucent.  (See  p.  216.) 

With  other  oxidize.d  copper  minerals,  sulphides,  native  copper. 


148  DETERMINATIVE  MINERALOGY  [SEC.  23 

H. 

85    G.  3.9-4.0    ALABANDITE  (Manganese  Glance,  Manganese  Blende),  MnS. 
4          Struct.  —  Granular,  compact;    isometric-tetrahedral  crystals  rare.     Cleav- 
age distinct,  three  directions  at  90°  (100);   brittle;  fracture  uneven. 

Color  iron-black,   tarnish  brownish  black.     Streak  olive-green.    Luster 
submetallic,  dull.    Opaque.     (See  p.  202.) 

In  veins  with  rhodochrosite  and  metallic  sulphides. 


G.  3.1-3.3    SCORODITE,  FeAs04-2H2O. 

Struct.  —  Pyramidal  orthorhombic  crystals,  sometimes  prismatic  or  tabular; 
botryoidal,  fibrous,  earthy,  amorphous.  Cleavage  imperfect,  two  directions 
at  60°  and  120°  (120);  brittle;  fracture  conchoidal,  uneven. 

Color  pale  green,  bluish  green,  blackish  green,  blue,  brown.  Streak 
white,  grayish,  greenish.  Luster  vitreous,  greasy.  Translucent.  (See  p. 
218.) 

With  arsenopyrite,  enargite,  limonite,  pyrite. 

G.  3.2-3.3    CROCIDOLITE  (Blue  Asbestos)  approx.  NaFe"Fe"/(Si03)3. 

Struct.  —  Asbestos-like;  long  delicate  flexible  fibers,  easily  separable;  com- 
pact, earthy. 

Color  and  streak  lavender-blue,  leek-green;  grayish-white  {amosite). 
Luster  silky,  dull.  Opaque.  (See  p.  222.) 

Cross-fiber  veins  in  banded  ferruginous  shales. 

G.  3.3-3.4    DIOPTASE  (Emerald  Copper),  H2CuSiO4;  Cu  40.3%. 

Struct.  —  Small  prismatic  hexagonal-rhombohedral  crystals;  crystalline 
aggregates,  crusts.  Cleavage  distinct,  three  directions  at  54°  and  126°  (lOll); 
brittle;  fracture  conchoidal,  uneven. 

Color  emerald-green,  dark  green.  Streak  green.,  Luster  vitreous.  Trans- 
parent to  opaque.  (See  p.  252.) 

With  other  oxidized  copper  minerals,  quartz,  limonite. 


5      G.  2.4-2.5    LAZURITE  (Lapis  Lazuli,  Native  Ultramarine), 
5  5        Struct.  —  Compact;     isometric    crystals    (dodecahedrons,    Fig.  7)    rare. 
Cleavage  inconspicuous,  six  directions  at  60°,  90°,  and  120°  (110);   brittle; 
fracture  uneven. 

Color  azure-blue,  violet-blue,  greenish  blue.     Streak  pale  blue.    Luster 
vitreous.     Translucent  to  opaque.     (See  p.  230.) 

At  contacts  in  crystalline  limestone,  with  pyrite,  calcite,  pyroxene.     Often 
intimately  mixed  with  calcite,  pyrite,  muscovite,  pyroxene,  etc. 

5  G.  2.9-3.4    HORNBLENDE  (an  amphibole),  silicate  of  Ca,Mg,Fe,Al,  etc. 

6  Struct.  —  Granular,   columnar,   fibrous,   radiated;    long  prismatic  mono- 
clinic  crystals  (pseudohexagonal),  often  with  rhombohedron-like  terminations; 
prism  angle  124°  ;  some  prisms  short.     Cleavage  perfect,  two  directions  length- 
wise at  56°  and  124°  (110);  brittle;  fracture  uneven,  splintery. 


SEC.  23]  PHYSICAL  TABLES  149 


Color  green,  black,  brown,  gray.  Streak  brown,  green,  yellow,  gray, 
white.  Luster  submetallic,  vitreous,  silky,  pearly.  Translucent  to  opaque. 
(See  pp.  222,  238.) 

Common  in  igneous  and  metamorphic  rocks  with  feldspars,  pyroxenes, 
chlorite,  quartz,  calcite. 

5  G.  3.2-3.6    PYROXENE,     Ca(Mg,Fe)(SiO3)2,     ranging    from     Diopside, 

6  CaMg(SiO3)2,  to    Hederibergite,  CaFe(SiO3)2;    often  come 
Al,  Mn,  and  Na. 

AUGITE  (a  pyroxene),  like  common  pyroxene  above,  with 
A12O3  up  to  15%  or  20%;  sometimes  alkali  metals,  Na  and  K. 

Struct. — Granular,  columnar,  rarely  fibrous;  lamellar  (diallage);  thick 
monoclinic  prisms  four-  or  eight-sided  (Figs.  40,  41).  Cleavage  sometimes 
distinct,  two  directions  lengthwise  at  87°  and  93°  (110);  often  prominent 
parting  crosswise  (001) ;  diallage  has  fine  lamellar  parting  one  direction  length- 
wise (100);  brittle;  fracture  uneven. 

Color  bright  to  dark  green,  grayish  green,  black  brown.  Streak  greenish, 
brownish,  grayish  to  white.  Luster  vitreous,  submetallic,  dull.  Trans- 
parent to  opaque.  (See  pp.  220,  222,  240.) 

Common  in  basic  igneous  rocks;  in  crystalline  limestones  with  garnet, 
chlorite,  amphibole,  wollastonite,  magnetite,  pyrite, 

51    G  9.0-9.7    URANINITE  (Pitchblende],  UO3,  UO2,  Pb,  Th,  La,  Y,  He,  Ra,  etc. 

Struct. — Botryoidal,  granular,  lamellar,  compact;  isometric  crystals  rare. 
Cleavage  none;  brittle;  fracture  conchoidal. 

Color  greenish  or  brownish  black,  pitch-black.  Streak  brownish  black, 
grayish  black,  olive-green.  Luster  pitch-like,  submetallic,  dull.  Opaque. 
(See  p.  210.) 

With  ores  of  silver,  lead,  copper,  bismuth;  also  in  pegmatites. 

5k     G.  2.6-2.8    TURQUOIS    (Turkis,    Turkish  Stone),   A12(OH)3PO4-H2O   with 
6  1.5-6.5%  Cu. 

Struct. — Compact,  reniform,  stalactitic,  incrusting;  thin  seams,  dissemi- 
nated; triclinic  crystals  rare.  Cleavage  none;  brittle;  fracture  conchoidal. 

Color  sky-blue,   bluish  green,   apple-green.      Streak  white,   pale  green. 
Luster  waxy,  dull.     Opaque  to  translucent.     (See  pp.  250,  256,  260.) 
Veins  and  seams  in  partly  decomposed  igneous  rocks. 

6  G.  3.5-3.6    Chloritoid  (Ottrelite),  H2FeAl2Si07;  some  Mg,  sometimes  Mn. 

7  Struct. — Foliated,  scaly,  rosette  groups;   rarely  tabular  triclinic  crystals, 
hexagonal    in    outline.      (Ottrelite,   oblong    scales).      Cleavage  perfect,  one 
direction   (001);    thin  flakes  brittle. 

Color  dark  gray,  greenish  gray,  greenish  black.  Streak  white,  grayish, 
pale  green.  Luster  pearly,  vitreous.  Translucent  .to  opaque.  (See  pp.  222, 
258,  260.) 

In  hornfels,  slate,  schist,  with  chlorite,  hornblende,  garnet,  corundum. 


150  DETERMINATIVE  MINERALOGY  [SEC.  23 

H. 

6  G.  4.0-4.5    Gadolinite,  FeGl2(YO)2(Si04)2;  some  Ce,  La,  Nd,  Pr,  Er,  Sc,  etc. 

7  Struct. — Compact,   disseminated,   nodular;    rough  prismatic  monoclinic 
crystals  rare.     Cleavage  none;   brittle;   fracture  conchoidal,  splintery. 

Color  black,  greenish  black,  brown;  thin  splinters  grass-green  to  olive- 
green.  Streak  greenish  gray.  Luster  vitreous,  greasy.  Translucent  to 
opaque.  (See  pp.  232,  252.) 

In  granite  and  pegmatite  with  quartz,  mica,  allanite,  fergusonite,  fluorite, 
molybdenite. 


DETERMINATION  OF  MINERALS  BY  MEANS 
OF  BLOWPIPE  AND  CHEMICAL  TESTS 


APPARATUS 

Blowpipe.  The  ordinary  jeweler's  blowpipe  of  brass,  10  or  12 
inches  long,  or  the  cheaper  one  of  japanned  iron,  serves  very  well. 
The  more  expensive  instrument  with  a  platinum  tip  is  more  durable 
(Figs.  59,  60,  61).  In  any  case  it  is  essential  that  the  tip  shall  be 
perforated  with  a  very  small,  smooth  hole. 


FIG.  59. 


FIG.  60. 


FIG.  61. 
Types  of  Blowpipes. 

Lamp.  Many  types  of  lamp,  or  even  a  candle,  may  be  successfully 
used  with  the  blowpipe,  (a)  The  ordinary  Bunsen  gas  burner 
(Fig.  62),  or  a  low  form,  more  convenient  for  blowpiping  (Fig.  63), 
with  a  tube  to  be  inserted  or  slipped  over  the  top.  The  tube  is 
flattened  to  a  narrow  slit  at  the  top  and  cut  off  slanting,  generally 

151 


152 


DETERMINATION  BY  BLOWPIPfe  TESTS 


with  projecting  points  left  to  form  a  rest  for  the  blowpipe  tip.  (6) 
A  lamp  to  use  olive  oil  or  other  vegetable  oil  (Fig.  64),  or  (c)  one 
using  tallow,  paraffin,  or  other  solid  fuel  (Fig.  65).  The  last  is  most 
convenient  for  portable  use.  It  is  lighted  with  a  match  and  the 
flame  is  then  blown  steeply  downward  for  a  few  seconds  in  order  to 
melt  some  of  the  fuel  next  to  the  wick.  The  heat  of  the  flame  then 


FIG.  62. 


FIG.  63. 


FIG.  64. 
Types  of  Blowpipe  Lamps. 


FIG.  65. 


keeps  it  going,     (d)  Ordinary  candles  (preferably  large  and  of  tallow) 
serve  very  well. 

Forceps.  For  most  purposes  plain  iron  forceps,  4  or  5  inches 
long  and  filed  down  to  small  points,  are  satisfactory.  Those  with 
platinum  points  are  better  but  very  expensive  (Figs.  66,  67,  68). 
The  points  of  the  "  cross-legged  "  forms  close  automatically  and 
hold  the  fragment  to  be  tested.  The  same  result  can  be  attained 
with  the  ordinary  tweezers  by  slipping  on  a  loop  of  small  wire  after 
the  fragment  is  in  place,  as  shown  in  Fig.  66. 


APPARATUS 


153 


Charcoal.  Best  from  soft  wood  (willow,  pine,  etc.).  Conven- 
ient sizes,  about  f  X 1 X4  inches,  may  be  purchased.  Used  as  a  sup- 
port in  many  operations  with  the  blowpipe  (Figs.  75,  76,  81),  and 
in  making  reductions  the  carbon  assists  the  flame. 

Platinum  Wire.  A  thin  platinum  wire,  26  B.  &  S.  gage,  about 
0.4  mm.  diameter  and  3  inches  long,  sealed  in  a  small  glass  tube  for 
a  handle  (Fig.  79).  Most  used  with  a  circular  loop,  |  inch  (3  mm.) 
in  diameter,  at  the  end  to  hold  a  bead  of  borax,  soda,  or  other  flux. 


FIG.  66. 


Fia.  67. 


FIG.  68. 
Forceps,  or  Tweezers  to  be  used  in  Blowpipe  Work. 

Open  and  Closed  Tubes.  To  be  made  of  "  hard,"  or  "  combus- 
tion "  tubing  4  or  5  mm.  internal  diameter  for  closed  tubes  and  7  or 
8  mm.  diameter  for  open  tubes.  For  open  tubes  cut  with  a  file  into 
4-inch  lengths  and  use  either  straight,  or  better,  with  a  bend  near 
one  end  (Fig.  78),  which  may  be  made  by  heating  until  the  glass  is 
soft.  For  closed  tubes  (Fig.  77),  cut  into  5-inch  lengths,  heat  the 
middle  in  the  Bunsen  flame  or  blast  lamp,  turning  slowly  in  order 
to  heat  all  sides  alike;  when  soft  pull  quickly  apart.  Hold  the  taper- 


FIG.  69. — Hammer  and  Anvil. 


FIG.  70.— Test  Tube  Holder. 


ing  part  of  each  tube  thus  formed  in  the  flame  and  pull  away  the 
slender  glass  tip. 

Hammer.  Any  small  hammer  will  serve.  For  the  special  ham- 
mer, a  wire  handle  is  best  (Fig.  69). 

Anvil.  Any  smooth  flat  block  of  iron  or  steel  (Fig.  69).  The 
flat  side  of  a  geologist's  hammer  or  prospector's  pick  is  good. 


154  DETERMINATION  BY  BLOWPIPE  TESTS 

Magnet.  A  magnetized  knife  blade  or  chisel  or  a  small  horse- 
shoe magnet. 

Test  Tubes.     Good  sizes  are  4  X  \  and  5  X  f  inches. 

In  addition  to  the  above  the  following  articles  will  be  found  con- 
venient in  the  laboratory.  For  portable  outfits  they  may  be  dis- 
pensed with. 

Test  Tube  Holder.  Of  brass  wire  (Fig.  70)  or  wood— for  holding 
hot  tubes. 

Streak  Plate.  Unglazed  porcelain;  a  convenient  size  is  1|X3 
inches.  A  clean,  fine-grained  whetstone  serves  very  well. 

Blue  and  Green  Glass.  Two  pieces  of  each,  2  or  3  inches  square, 
for  observing  flame  colors. 

Watch  Glasses.     Shallow,  2  inches  in  diameter. 

Test  Tube  Support.  Wood,  with  several  holes  larger  than  the 
tubes.  Easily  made. 

A  gate  Mortar.  If  inches  diameter  or  larger,  with  agate  pestle. 
Fragments  can  be  ground  under  the  hammer,  and  if  the  anvil  is 
placed  in  a  paper  tray  of  sufficient  depth  (Fig.  69),  the  particles  that 
fly  will  be  caught. 

Diamond  Mortar.  Of  steel;  two-piece  form  is  best.  Useful 
when  only  small  particles  of  a  mineral  are  obtainable. 

Glass  Funnel.     Two  inches  in  diameter  or  larger. 

Filter  Paper.     Round  and  twice  the  diameter  of  the  funnel. 

Charcoal  Brush.  For  removing  sublimates  from  charcoal  an 
old  toothbrush  or  any  stiff  brush  may  be  used;  or  sublimates  may 
be  scraped  off  with  a  knife. 

Plaster  Tablets.  Thin  paste  of  plaster  of  Paris  is  spread  about 
f  inch  thick  on  a  sheet  of  glass  that  has  been  slightly  oiled.  While 
still  soft  cut  the  paste  with  a  knife  into  rectangles  about  1|X4  inches. 
These  are  readily  removed  after  the  plaster  hardens.  Used  for  sup- 
port, like  charcoal,  and  show  some  sublimates  better. 

Porcelain  Crucible.  With  support.  Sometimes  useful  for  burn- 
ing a  filter  paper. 

REAGENTS 
To  be  used  dry: 

Sodium  Carbonate,  or  soda,  Na2COs;  or  sodium  bicarbonate, 
common  baking  soda,  NaHCOs. 

Sodium  Tetraborate,  or  borax,  Na2B407  •  10H20. 

Borax  Glass  may  be  prepared  as  required  by  making  borax  beads 
(p.  168)  and  pulverizing  them  for  use  as  a  flux. 


REAGENTS  155 

Sodium  Ammonium  Phosphate,  also  called  "  phosphorus  salt  "  and 
"  microcosmic  salt,"  HNaNH4PO4-4H2O.  Loses  NH4OH  and 
4H20  on  heating,  becoming  sodium  metaphosphate  (NaPOs),  abbre- 
viated s.ph. 

Test  Papers,  small  strips  of  blue  and  red  litmus  paper  and  yellow 
turmeric  paper. 

Occasional  use  will  also  be  found  for  the  following: 

Potassium  Bisulphate,  KHS04. 

Turner's  Flux,  1  part  finely  powdered  fluorite  (CaF2)  with  3  parts 
potassium  bisulphate  (KHS04). 

Von  Kobell's  Flux,  1  part  potassium  iodide  (KI),  2  parts  sulphur 
(S),  and  1  part  potassium  bisulphate  (KHSO4). 

Tin,  foil  or  granulated.  Scraps  of  tin  cans  or  other  tin  plate  will 
serve.  Also  Zinc,  either  granulated  or  scraps  of  sheet  metal; 
Potassium  Nitrate,  KNO3;  and  powdered  Galena,  PbS,  Gypsum, 
CaSO4-2H2O,  and  Fluorite,  CaF2. 

To  be  used  in  liquid  form: 

Water,  H20,  distilled  or  rain  water  is  best;  for  most  purposes  any 
clear  water  that  is  not  "  hard  "  will  serve. 

Hydrochloric  Acid,  HC1  ("  muriatic  acid  "),  for  most  purposes 
the  concentrated  acid  as  obtained  from  the  supply  houses  (sp.  gr. 
1.20)  is  diluted  with  an  equal  quantity  of  water,  giving  a  solution  a 
little  stronger  than  5/N. 

Other  mineral  acids  are  more  dangerous  to  handle  and  less  useful 
than  hydrochloric.  Many  of  the  reagents  that  follow  are  rarely 
needed ;  on  the  other  hand,  most  of  those  used  in  a  chemical  laboratory 
will  occasionally  be  found  useful. 

Nitric  Acid,  HNO3  ("aqua  fortis  ").  To  dilute  the  concen- 
trated acid  (sp.  gr.  1.42)  to  approximately  5/N,  add  two  volumes  of 
water. 

Nitrohydrochloric  Acid  ("  aqua  regia "),  3  parts  hydrochloric 
and  1  part  nitric  acid. 

Sulphuric  Acid,  H2S04  ("  oil  of  vitriol  ").  In  diluting  add  the 
concentrated  acid  (sp.  gr.  1.84)  very  slowly  to  6  volumes  of  water,  for 
approximately  5/N. 

Ammonium  Hydroxide,  or  ammonia,  NH4OH.  Add  to  the  con- 
centrated solution  (sp.  gr.  .90)  three  volumes  of  water,  for  approxi- 
mately 5/N.  This  solution  will  neutralize  an  equal  volume  of  the 
dilute  acids. 


156  DETERMINATION  BY   BLOWPIPE  TESTS 

Potassium  Hydroxide,  KOH  ("  caustic  potash  ").  Best  kept  as 
sticks  broken  to  short  bits  and  placed  in  a  well-stoppered  bottle — 
to  be  dissolved  in  a  little  water  as  needed. 

Ammonium  Molybdate,  (NILj^MoO*.  Dissolve  the  crystals  in 
water  that  has  been  made  alkaline  with  ammonia.  For  use 
acidify  a  little  of  this  solution  in  a  test  tube  with  HNOs;  the  ppt. 
that  forms  is  quickly  cleared  up  by  further  addition  of  acid. 

Cobalt  Nitrate,  Co(NOs)2.  Dissolve  the  crystals  in  10  parts  of 
water.  A  dropping  bottle  holding  one  or  two  ounces  is  convenient 
for  laboratory  use. 

Ammonium  Carbonate,  (NH^COs.     Dissolve  in  water  as  needed. 

Ammonium  Oxalate,  (NH4)2C2O4-2H2O.  Dissolve  in  water  as 
needed. 

Sodium  Phosphate,  Na2HPO4.     Dissolve  in  water. 

Barium  Chloride,  BaCk.     Dissolve  in  water. 

Barium  Hydroxide,  Ba(OH)2.     Dissolve  in  water. 

Silver  Nitrate,  AgNOs.  Dissolve  in  water  and  keep  in  a  bottle 
of  amber  color  or  one  well  wrapped  with  opaque  paper. 

Potassium  Ferrocyanide,  K4Fe(CN)e-3H20.     Dissolve  in  water. 

Potassium  Ferricyanide,  K6Fe2(CN)i2.  Dissolve  a  little  at  a 
time  in  water  as  needed.  The  solution  does  not  keep  well. 

Hydrogen  Peroxide,  H202.  The  ordinary  3%  solution  serves. 
Keep  in  bottle  of  amber  color  or  one  wrapped  in  opaque  paper. 

Stannous  Chloride,  SnCb,  when  required,  may  be  prepared  by 
treating  tin  foil  with  HC1. 

Dimethylglyoxime,  C4HgO2N2.  Dissolve  in  100  times  its  weight 
of  alcohol.  Useful  in  testing  for  Ni. 


BLOWPIPE  OPERATIONS  AND  CHEMICAL  TESTS 

Blast.  The  blast  of  the  blowpipe  should  not  be  blown  from  the 
lungs  and  should  not  interfere  with  regular  breathing.  Distend  the 
cheeks  fully  and,  while  breathing  through  the  nose,  allow  the  air  to 
escape  from  the  mouth  through  the  blowpipe  without  making  any 
effort  to  blow.  Before  the  supply  is  exhausted  distend  the  cheeks 
again  from  the  lungs.  In  this  way  the  blast  may  be  continued  for 
several  minutes,  when  necessary,  without  fatigue.  If  the  blowpipe 
tip  is  in  good  condition  the  flame  will  be  smooth,  steady,  and  silent 
(Figs.  72-76). 

Flames.  A  candle  flame  or  luminous  gas  flame  consists  of  3  con- 
centric parts  (Fig.  71):  (a)  an  inner  cone  of  unburned  gases;  (&)  a 


BLOWPIPE  "OPERATIONS  AND  CHEMICAL  TESTS 


157 


mantle  of  unhurried  gas  or  vapor,  full  of  glowing  particles  of  carbon, 
where  carbon  monoxide  (CO)  and  water  (EkO)  are  forming  by  com- 
bustion; (c)  a  hot,  non-luminous  mantle  of  the  products  of  complete 
combustion,  carbon  dioxide  (CO2)  and  water  (H20)  mingling  with  the 
surrounding  air,  and  hence  with  an  excess  of  oxygen.  Hot  fuel  is 
in  excess  in  (&),  hence  it  is  reducing  in  its  action;  but  the  tempera- 
ture is  too  low  for  vigorous  reduction.  The  excess  of  oxygen  makes 
(c)  oxidizing,  and  it  is  also  hotter.  A  non-luminous  Bunsen  or 
alcohol  flame  differs  only  in  lacking  the  incandescent  carbon  in  (6). 


FIG.  71. 


FIG.  72. 


FIG.  71. — Candle  flame:  (a)  Unburned  gases;  (6)  burning  gases,  forming  H2O, 
CO,  and  luminous  C;  (c)  hot  combustion  products,  H2O,  CO2  mingled  with 
O  from  surrounding  air.  The  luminous  gas  flame  is  the  same. 

FIG.  72. — Blowpipe  flame:  (a)  Mixture  of  unburned  gas  and  air  from  the  blow- 
pipe; (6)  burning  gas  gives  intense  heat  and  slight  reducing  action;  (c)  and 
beyond,  hot  combustion  products  with  excess  of  O  from  blowpipe — oxidizing 


In  determinative  mineralogy  these  flames  are  often  directed 
laterally  or  inclined  downward  by  the  use  of  the  blowpipe.  For 
oxidizing  effects  the  tip  should  be  inserted  slightly  into  the  flame,  as 
in  Fig.  72,  thereby  mixing  more  oxygen  with  the  gases  at  the  base. 
The  best  reducing  effect  is  obtained  by  withdrawing  the  tip  a  little 
from  the  flame  and  blowing  very  gently  (Fig.  73).  The  flame  should 
not  be  sooty,  but  a  little  luminous  carbon  should  extend  down  the 
whole  length  of  it. 

Ignition:  Fusion.  The  application  of  intense  heat  is  commonly 
called  ignition.  The  hottest  flame  is  entirely  non-luminous  and  the 
hottest  part  of  it  is  just  beyond  the  visible  blue  tip.  The  fusibility 
of  a  mineral  is  tested  at  this  point  by  strongly  heating  an  elongated 


158 


DETERMINATION  BY  BLOWPIPE  TESTS 


fragment  not  more  than  1.5  mm.  (^  of  an  inch)  in  thickness;  that 
is,  thinner  than  the  "  lead  "  of  an  ordinary  pencil.  This  is  held  in 
the  forceps  so  that  it  projects  into  the  flame  (Fig.  74).  The  mineral 
may  fuse  quietly,  or  with  intumescence  (bubbling  and  swelling  up), 


FIG.  73. — Blowpipe  flame:    (6)  Strong   reducing  flame  (r.f.),  with  gentle  blast 
and  more  gas  than  used  in  o.f. 

or  with  exfoliation  (splitting  into  leaves  or  flakes).  The  result  may 
be  fusion  to  a  bead  of  colored  or  colorless  glass,  clear  or  filled  with 
bubbles;  or  to  a  white,  opaque  enamel.  If  infusible  the  mineral  may 
remain  unchanged,  or  it  may  change  color,  or  become  opaque,  etc. 
All  of  these  properties  should  be  carefully  noted. 


FIG.  74. — Testing  fusibility,  showing  maximum  size  of  fragment,  manner  of 
holding  it,  and  position  in  the  flame. 

Decrepitation.  The  violent  breaking  away  of  particles  with  little 
crackling  explosions  owing  to  sudden  unequal  heating  or  to  the 
expansion  of  minute  inclusions  of  water  or  liquid  carbon  dioxide  is 
called  decrepitation.  This  sometimes  interferes  seriously  with  the 
determination  of  fusibility.  By  first  heating  the  mineral  very 
gradually  and  gently  in  the  Bunsen  flame  this  difficulty  may  some- 
times be  avoided ;  otherwise  heat  a  few  fragments  in  a  closed  tube 
until  decrepitation  ceases  and  select  a  fragment  of  suitable  size,  if 


BLOWPIPE  OPERATIONS  AND  CHEMICAL  TESTS          159 

such  remains.  When  this  fails,  make  a  thin  paste  of  the  finely 
powdered  mineral  with  water,  spread  a  little  of  this  on  charcoal  and 
heat,  at  first  very  gently,  then  intensely.  The  crust  thus  formed  can 
be  taken  up  carefully  in  the  forceps  and  tested  for  fusibility. 

Scale  of  Fusibility.  The  degree  of  fusibility  of  minerals  is  indi- 
cated by  numbers  referring  to  the  following  scale.  Comparison 
should  be  made  on  fragments  of  about  the  same  size.  Penfield 
recommends  a  standard  size  of  about  1.5  mm.  in  diameter,  as  ex- 
plained above.  With  the  more  difficultly  fusible  minerals,  however, 
a  much  smaller  fragment  with  a  very  thin  edge  or  fine  point  should 
be  tested  before  deciding  that  it  is  infusible. 


SCALE  OF  FUSIBILITY 

(Penfield's  modification  of  von  Kobell's  scale) 

(Minerals  named  in  parentheses  have  about  the  same  fusibility 
as  the  standard.) 

1.  Stibnite,  Sb2S3.     Fragments  larger  than  standard  size  fuse  easily 

in  a  luminous  flame;  fuses  easily  in  closed  tube  below  red  heat. 
(Realgar,  orpiment,  sulphur.) 

2.  Chalcopyrite,  CuFeS2.     Standard  size  fragment  fuses  in  luminous 

flame ;  small  fragment  fuses  in  closed  tube  at  red  heat.  (Galena, 
arsenopyrite,  apophyllite.) 

3.  Almandite    (Garnet),    Fe3Al2(SiO4)3.     Standard    fragment    fuses 

readily  to  globule  with  blowpipe;  only  thinnest  edges  rounded  in 
luminous  flame.     (Malachite,  wernerite,  stilbite.) 

4.  Actinolite,  Ca(Mg,Fe)3(SiO3)4.     Edges  easily  rounded  on  stand- 

ard fragment;  fine  splinter  fuses  easily  to  globule.     (Tremolite, 
wollastonite,  barite.) 

5.  Orthoclase,  KAlSisOg.     Edges  of  standard  fragment  rounded  with 
difficulty;    only  finest  splinters  fuse   to   globule.     (Sphalerite, 
biotite,  scheelite.) 

6.  Bronzite,   (Mg,Fe)Si03.     Only  finest  points  and  thinnest  edges 
can  be  rounded  at  all.     (Enstatite,  calamine,  serpentine.) 

Quartz  may  be  added  as  No.  7^  to  represent  minerals  that  are 
infusible  in  the  blowpipe  flame. 


160  DETERMINATION  BY  BLOWPIPE  TESTS 

Flame  Colors.  Some  minerals  on  ignition  impart  to  the  blow- 
pipe flame  a  distinct  color,  which  is  best  seen  against  a  dark  back- 
ground. It  is  often  more  distinct  when  a  trace  of  fine  powder  is 
introduced  into  the  Bunsen  flame  with  a  clean,  dry  platinum  wire. 
Hold  the  wire  first  in  the  cool  edge  of  the  flame,  at  the  base,  then 
raise  it  gradually  into  the  hottest  central  part  near  the  tip.  If  the 
wire  is  first  moistened  with  water  a  larger  quantity  will  adhere,  and 
this  is  sometimes  advantageous.  Instead  of  water  dilute  HC1  is 
often  helpful,  and  with  some  minerals  concentrated  H2S04. 

Absorption-light  filters  are  useful  in  analyzing  mixed  flames. 
Blue  and  green  glass  are  commonly  used  for  this  purpose,  but  the 
Merwin  flame-color  screen  is  more  effective.  It  consists  of  strips  of 
transparent  blue  and  violet  celluloid  that  are  partly  overlapped, 
forming  three  color  divisions.  In  use  the  glass  or  screen  is  held 
close  to  the  eyes  and  the  colored  flame  viewed  through  it.  The 
colors  imparted  by  various  substances  and  the  effects  of  absorption- 
filters  are  given  in  the  table  on  the  opposite  page. 

Roasting  on  Charcoal.  Spread  a  fine  powder  of  the  mineral 
thinly  on  charcoal  and  heat  with  a  small  oxidizing  flame,  a  consider- 
able distance  beyond  the  tip  of  the  blue  and  at  no  more  than  a  dull 
red  heat  (Fig.  75).  If  the  mineral,  fuses  easily  heat  intensely  till  the 


FIG.  75. — Roasting  on  charcoal;  use  very  small  o.f.,  scarcely  red  heat. 

volatile  constituents  are  driven  off,  then  pulverize  with  a  little  pow- 
dered charcoal  and  repeat  the  roasting  with  the  mixture,  using  the 
small  oxidizing  flame  and  low  temperature  again. 

Ignition  on  Charcoal.  With  the  edge  of  a  small  coin  make  a 
slight  depression  near  one  end  of  the  coal  and  place  in  it  a  few 
grains  of  the  mineral,  not  larger  than  pin  heads.  Hold  the  length 
of  the  coal  in  line  with  the  flame  and  tilted  towards  it  (Fig.  76),  in 
order  to  catch  any  sublimate  that  may  form. 

First  heat  for  only  2  or  3  seconds  v/ith  a  small  gentle  oxidizing 
flame,  as  in  roasting  (Fig.  75),  not  allowing  the  visible  flame  to  come 


BLOWPIPE  OPERATIONS  AND  CHEMICAL  TESTS 


161 


FLAME  COLORS 

(For  abbreviations,  see  page  285) 
(Merwin  screen:  1.  Blue;  2.  Overlap;  3.  Violet) 


Color. 

Shade. 

Substance.               Absorption-effects.      Remarks. 

Red 

Crimson 

Sr 

1,  2,  Invisible;    3.  Crimson.      Faint    yellow 
through  green  glass.     Alk.  after  ign. 
Sr  sol.  with  few  drops  BaQ2  sol.  gives   red 
flame  after  green. 

Red 

Crimson 

Li 

1,  2.  Invisible  ;     3.  Crimson.     Invisible 
through  green  glass.     Not  alk.  after  ign. 
Li  sol.  with  few  drops   BaCl2  sol.  gives  red 
flame  before  green. 

Red 

Yellowish  to 
orange 

Ca 

1.  Gnh.  yel.;  2.  Faint  grn.;  3.  Pale  crimson. 
Invisible   through  green  glass.      Improved 
by  HC1.     Alk.  after  ign.                                  | 

Yellow 

Intense 

Na 

Intense  and  persistent.     1,  2,  3.  Invisible. 
Invisible  through  blue  glass. 

Green 

Yellowish 

Ba 

1.  Green;  2,  3,  Pale  green.     Alk.  after  ign. 

Green 

Yellowish 

B 

1.  Green;     2,    3.  Pale    green.      Use     cone. 
H2SO4;  for  insol.  minerals  use  3  parts  Turn- 
er's flux.     (Turmeric  test  decisive.) 

Green 

Yellowish 

Mad, 

1.  Emerald;    2.  Pale  bluish  green;  3.    Pale 
lavender. 

Green 

Pale  yelh. 

Mo 

From  oxide  or  sulphide. 

Green 

Emerald 

CuO 
Cul 

With  HC1  blue  flame  tinged  with  green. 

Green 

Pale 

Te 

Sb 

Green 

Pale  bluish 

P 

1.  Grn.;    2.  Pale  grn.;    3.  Light  violet-red. 
Use  cone.  H2SO4. 

Green 

Bluish 

Zn 

Bright  streaks  in  outer  part  of  flame. 

Blue 

Azure 

CuCl2 

Outer  fringe  of  emerald  green. 
1.  Bright  grn.;   2.  Pale  grn.;    3.  Blue,  with 
green  fringe. 

Blue 

Indigo 

Se 

Characteristic  radish-like  odor. 

Blue 

Pale  azure 

Pb 

Green  tinge  in  outer  part  of  flame. 

Blue 

Pale 

As 

Characteristic  garlic  odor. 

Violet 

Pale 

K 

1.  Blue-  violet;    2.  Faint  violet-red;  3.  Red- 
dish-violet.    Purplish-red       through    blue 
glass. 

162  DETERMINATION  BY  BLOWPIPE  'TESTS 

near  the  mineral.  Note  reactions,  if  any:  (1)  decrepitation,  (2) 
deflagration,  (3)  visible  fumes.  The  moment  the  heat  is  stopped 
seek  for  (4)  odors,  and  observe  (5)  any  change  in  color  and  (6) 
color  and  position  of  sublimate,  if  any.  (Caution:  Do  not  mistake 
ash  for  sublimate.)  If  the  mineral  blackens,  test  when  cold  for 
(7)  magnetism.  Repeat  the  oxidizing  flame  with  increasing  inten- 
sity, using  fresh  material  if  necessary,  until  the  reactions  are  clearly 
determined.  Next  use  the  reducing  flame  (Fig.  76)  on  the  oxidized 
material,  beginning  gently  and  increasing  the  intensity.  Look  for 


FIG.  76. — Reduction  on  charcoal,  with  sublimates,  when  formed,  at  (d~)  and  be- 
yond. For  comparison  burn  a  spot  on  the  coal  and  observe  the  color  and 
texture  of  the  ash.  Note  that  the  grain  shows  distinctly  in  the  ash,  while 
sublimates  tend  to  conceal  it. 

the  above  reactions  and  also  (8)  globules  of  metal  that  may  be  reduced. 
If  the  reactions  are  weak  and  uncertain  mix  the  powdered  mineral 
with  three  times  its  volume  of  soda  and  a  little  borax  and  charcoal 
powder,  then  fuse  on  charcoal  for  a  full  minute  with  the  most  intense 
heat. 

Reduction  of  Metals.  Mix  equal  volumes  of  finely  powdered 
mineral,*  charcoal,  and  borax  with  3  volumes  of  soda.  Moisten 
slightly  with  water  and  place  a  mass  the  size  of  a  small  pea  in  a  shal- 
low depression  on  the  charcoal.  Fuse  in  a  strong  reducing  flame  for 
two  or  three  minutes  without  interruption,  unless  a  bead  of  metal 
becomes  distinctly  visible  in  a  shorter  time.  If  no  metal  is  visible 
pry  off  the  assay  with  a  chisel  or  knife,  removing  with  it  a  little  of  the 
charcoal  on  which  it  rests;  grind  to  a  fine  powder  in  an  agate  mortar, 
and  while  continuing  the  grinding,  allow  water  to  flow  gently  from 
the  tap  upon  the  hand  and  into  the  mortar.  The  surplus  soda  dis- 

*  If  the  mineral  yields  S,  As,  or  Sb  in  o.f.  on  charcoal,  it  must  first  be  thor- 
oughly roasted  in  order  to  convert  it  into  oxides. 


BLOWPIPE  OPERATIONS   AND   CHEMICAL  TESTS 


163 


SUBLIMATES  ON  CHARCOAL 

(For  abbreviations,  see  page  285) 


Near  Assay. 

Dist.  from  Assay. 

Substance. 

Remarks. 

White,  very  vola- 
tile 

White  to  grayish 

As2O3 

Mostly  far  from  assay;  often 
strong  garlic  odor 

Dense  white,  vola- 
tile 

Gray  or  slightly 
brownish 

White, 
TeO2 
Gray,  Te 

Volatilizes  in  r.f.,  coloring 
flame  pale  green 

Dense  white,  vola- 
tile 

Bluish 

Sb2O3  and 
SbSbO* 

Heavy  near  the  assay 

White 

White  to  bluish 

Chlorides  of  Cu,  Pb,  Hg,  NH4,  and  alkalis 

Pale  yel.  to  wh. 
hot;  wh.  cold; 
non-vol.  ino.f. 

Faint  white 

Sn02 

Moistened  with  Co(NO3)2  and 
ignited,  subl.  becomes  bluish- 
green 

Pale  yel.  hot;  wh. 
cold;  vol.  ino.f. 

Bluish 

Mo03 

Touched  with  r.f.,  subl.  be- 
comes azure-blue.  Cu-red 
MoO2  subl.  next  to  assay 

Canary-yel.  hot; 
wh.  cold;  non- 
vol.  in  o.f. 

Faint  white 
(See  p.  189) 

ZnO 

Moistened  with  Co(NO3)2  and 
ignited  the  subl.  becomes 
green 

Yel.  hot;  pale  yel. 
cold;  vol.  ino.f. 
and  r.f  . 

Dense        white 
with     bluish- 
wh.  border 

PbO 
PbSO3 
PbSO4 

Forms  when  galena  and  other 
Pb  sulphides  are  heated  very 
hot  on  charcoal 

Dark  yel.  hot; 
S-yel.  cold;  vol. 
hi  o.f.  and  r.f. 

Bluish-white 

PbO 

Heated  with  von  Kobell's  flux 
forms  volatile  yelh.-grn. 
subl.,  PbI2 

Dark  orange-yel. 
hot;orange-yel. 
cold;  vol.  in  o.f. 
and  r.f. 

Greenish-white 

Bi203 

Fused  with  von  Kobell's  flux 
in  small  o.f.  forms  yel.  subl. 
fringed  by  brilliant  red 

Nearly     blk.     to 
rdh.-brn.;  vol. 
in  o.f.  and  r.f. 

Yellow 

CdO 

Iridescent  when  very  thin 

Rdh.  to  deep  lilac 

Ag  with 
Pb  and  Sb 

Ag  alone  gives  slight  bnh.  subl. 
after  long  ignition 

Copper-red 

White 

MoO2 
MoO3 

Touched  with  r.f.,  white  subl. 
becomes  azure-blue 

Steel-gray,  faint 
metallic  luster; 
very  vol. 

White;  may  be 
tinged  red 

White, 
SeO2 
Red,  Se 

Subl.     colors    r.f.     azure-blue. 
Characteristic     radish-like 
odor 

164 


DETERMINATION  BY  BLOWPIPE  TESTS 


solves  and  the  powdered  charcoal  is  floated  away  by  the  overflow. 
Globules  of  metal,  flattened  by  the  grinding,  will  appear  as  bright 
scales  on  the  pestle  and  in  the  mortar. 

Transfer  the  metal  to  a  watch  glass,  add  a  drop  or  two  of  HNOs, 
warm  gently  and  add  an  equal  amount  of  water. 

White  Metal.  Sn  changes  to  white  insoluble  oxide;  Pb  soluble 
and  gives  white  precipitate  with  a  drop  of  H^SCU;  Ag  soluble  and 
gives  with  a  drop  of  HC1  a  white  precipitate  which  is  soluble  in 
ammonia;  Pt  insoluble  in  HNOs,  soluble  in  aqua  regia.  Evaporate 
to  dryness,  add  water  and  KC1,  a  yellow  precipitate  confirms  Pt. 

Yellow  or  Red  Metal.  Cu  soluble  in  HNOs  and  gives  reddish- 
brown  precipitate  with  potass,  f errocyanide ;  Au  insoluble  in  HNOs, 
soluble  in  aqua  regia.  Evaporate  to  dryness,  add  a  drop  or  two  of 
water  and  a  drop  of  dilute  solution  of  SnCk.  A  violet-brown  pre- 
cipitate confirms  Au, 


IODIDE  SUBLIMATES  ON  PLASTER  AND  CHARCOAL 

(For  abbreviations,  see  page  285) 


On  Plaster. 

Substance. 

On  Charcoal. 

Chrome-yellow,  volatile 

PbI2 

Chrome-yel.;   gnh.  if  thin; 
volatile 

Yellow  to  orange;  very  volatile 

AsI3 

Faint  yellow 

Orange  to  red;   disappears  in  strong  am- 
monia fumes 

SbI3 

Faint  yellow 

Scarlet  with  yel.;    if  strongly  heated  is 
dull  yel.  and  blk. 

Hgl 

Faint  yellow 

Rdh.-brn.,  nearly  scarlet 

SeI4 

Does  not  show  on  charcoal 

Chocolate-brn.,  with  underlying  scarlet; 
in   ammonia    fumes   becomes   orange 
and  then  cherry-red 

BiI3 

Bright    red;    yellow  near 

assay 

Purplish-brn.,  darker  border 

TeI4 

Does  not  show  on  charcoal 

Ultramarine-blue,  deep 

MoI4 

Does  not  show  on  charcoal 

On  Plaster  Tablets.     The  tablet  may  be  placed  on  charcoal  as  a 
support.    A  little  of  the  pulverized  mineral  is  mixed  with  von  Kobell's 


BLOWPIPE  OPERATIONS  AND   CHEMICAL  TESTS          165 

flux  and  fused  near  one  end  of  the  tablet.  Volatile  iodides  are  formed, 
many  of  which  produce  characteristic  sublimates  on  the  cool  part  of 
the  plaster.  The  same  process  may  be  used  on  charcoal,  and  in  the 
accompanying  table  the  results  are  compared  with  those  on  plaster. 


FIG.  77. — Heating  in  closed  tube  (c.t.):    Hold  the  tube  with  the  fingers  only, 
and  hold  it  in  nearly  horizontal  position. 


FIG.  78. — Heating  in  open  tube  (o.t.):  Use  tube  holder  and  allow  part  of  the 
flame  to  play  up  the  steeply  inclined  arm  of  the  tube,  in  order  to  insure  a 
sufficient  draft,  or  blow  into  the  lower  end  with  the  blowpipe. 

In  Closed  Tube.  The  object  is  to  heat  the  mineral  with  little  air, 
and  hence  with  little  oxidation.  Use  small  fragments;  fine  powder 
adheres  to  the  side  of  the  tube  and  may  interfere  with  sublimates. 
Volatile  emanations  that  give  an  odor  or  condense  as  a  sublimate  or 
a  liquid  on  the  side  of  the  tube  are  to  be  specially  noted;  also  decrepi- 
tation, phosphorescence,  fusion,  change  in  form  or  color,  or  mag- 


166 


DETERMINATION   BY  BLOWPIPE   TESTS 


netism.  The  upper  end  of  the  tube  must  be  kept  cool,  and  this  is 
best  assured  by  holding  it  with  the  fingers  only  and  keeping  it  nearly 
horizontal  (Fig.  77). 

SUBLIMATES  IN  CLOSED  TUBE 
(For  abbreviations,  see  page  285) 


Hot. 

Cold. 

Substance. 

Remarks. 

Colorless  liquid;  easily 
volatile 

Cols,  liquid 

H20 

Neutral    or    acid;     rarely 

alkaline 

White  solid 

White  solid 

PbCl2,  SbCU,  As2O3,  Sb2O3,  NH4  salts 

Gray  metallic  liquid  globules 

Hg 

Unite  by  rubbing  with  strip 
of  paper 

Pale  yel.  to  cols,  liquid; 
difficultly  volatile 

Cols,    to    wh. 
globules 

TeO2 

From  Te  and  some  com- 
pounds 

Dark  yellow  to  red 
liquid;   easily  volatile 

Yel.  xln.  solid; 
pale  in  small 
amount 

S 

From  S  and  some  sulphides 

Dark  red  liquid,  nearly 
blk.;  easily  volatile 

Rdh.-yel. 

transparent 
solid 

AsS 
As2S3 

From  sulphides  and  sul- 
pharsenites 

Black  solid;    difficulty 
volatilized 

Rdh.-brown 

Sb2OS2 

Sulphides  and  sulphanti- 
monites 

Brilliant  blk.,  solid;  often  gry.  and  xln. 
near  heated  end 

As 

From  As  and  arsenides. 
Break  off  closed  end  and 
heat  subl.  for  garlic  odor 

Brilliant  blk,.  solid 

HgS 

Subl.  rubbed  gives  red 
powder 

Blk.  fusible  globules 

Te 

Te  and  tellurides;  usually 
some  TeO2  formed  (see 
above) 

Blk.  fusible  globules;  smallest  deep  red 
by  transmitted  light 

Se 

Often  also  wh.  xln.  SeO2 

In  Open  Tube.     The  object  is  to  heat  the  mineral  with  a  good 
supply  of  air  for  oxidation.     Place  finely  powdered  mineral  near  one 


BLOWPIPE  OPERATIONS  AND  CHEMICAL  TESTS 


167 


end  of  the  tube  (at  the  elbow  if  the  tube  is  bent).  Hold  the  tube 
steeply  inclined,  with  the  powder  at  the  lower  end,  using  a  holder, 
since  the  whole  tube  must  become  hot.  An  edge  of  the  flame  should 
play  constantly  (or  very  frequently)  on  the  upright  portion  of  the 
tube  in  order  to  insure  an  active  draft.  This  may  be  facilitated  also 
by  blowing  into  the  lower  end  of  the  tube  with  the  blowpipe.  Use 
but  little  of  the  mineral,  in  order  to  avoid  choking  the  tube  and  reduc- 
ing the  draft;  also,  with  a  large  amount,  volatilization  may  exceed 
oxidation  and  the  results  will  be  mixed  and  indecisive. 
Observe  odors,  visible  fumes,  and  sublimates. 

SUBLIMATES  IN  OPEN  TUBE 
(For  abbreviations,  see  page  285) 


Color  and  Character. 

Substance. 

Remarks. 

White  xln.,  readily  volatile 

AszOa 

Xln.  (octahedrons)  on  the  warm 
glass 

White  xln.,  readily  volatile 

Se02 

Usually  radiating  xls.  ;  often  a  little 
redSe 

White  xln.,  slowly  volatile 

Sb203 

Xls.  are  octahedrons  and  prisms 

White  non-voi.,  infusible 

PbSO3 
PbS04 

Slight  deposit;  mostly  on  lower  side 
of  tube  near  assay 

Pale  yel.  globules;  slowly  vol. 

TeO2 

Globules  white  or  colorless  when 
cold 

Pale  yel.  hot;    wh.  cold; 
amorph.,  infus.,  non-vol 

SbSb04 

Dense  wh.  smoke;  subl.  mostly  on 
under  side  of  tube;  usually  some 
volatile  Sb2O3 

Pale  yel.  hot;    wh.  cold;    fus. 
and  vol.  at  red  heat 

MoO3 

Network  of  delicate  xls.  near  assay 

Yel.  to  orange;  easily  vol. 

S,AsS 

These  sublimates  result  from  too 
rapid  heating;  will  not  form  with 
proper  draft  and  oxidation.  Heat 
tube  above  assay  first,  then  di- 
rectly under  it 

Blk.  hot;  brn.  cold;  dif.  volatile 

Sb2OS2 

Brilliant  blk.;  volatile 

As,HgS 

Gry.    metallic    globules;    vola- 
tile 

Hg 

Unite  by  rubbing  with  strip  of  paper 

Red,  volatile 

Se 

Often  with  white  SeO2  (see  above) 

168 


DETERMINATION   BY  BLOWPIPE  TESTS 


O 


In  Borax  Bead.  A  round  loop  (£  inch  diameter)  of  platinum 
wire  may  be  made  conveniently  by  bending  it  around  the  tapering 
part  of  a  pencil  near  the  point  (Fig.  79a).  The  loop  is  heated  in  the 
Bunsen  or  blowpipe  flame  and  dipped  into  the  powdered  borax. 
The  part  that  adheres  is  fused  to  a  clear  globule  (Fig.  80);  this  is 
again  dipped  into  the  borax,  and  the  process  is  repeated  until  a 
spherical  bead  is  obtained.  The  hot  bead  is 
touched  lightly  to  a  fine  powder  of  the 
mineral  *  and  is  then  heated  thoroughly  in 
the  oxidizing  blowpipe  flame,  f  The  degree 
of  solubility  of  the  particles  and  the  colors, 
if  any,  imparted  to  the  bead  are  carefully 
noted.  It  is  then  heated  continuously  for 
some  time  in  the  reducing  flame,  and  any 
change  noted.  The  quantity  of  the  powdered 
mineral  in  the  bead  is  gradually  increased 
until  a  distinct  reaction  is  obtained  or  until 
the  bead  is  saturated  with  it. 

A  bead  about  half  the  size  described  above 
may  be  made  on  the  end  of  the  wire  without 
a  loop  by  holding  it  horizontally  or  pointed 
somewhat  downward  in  the  flame.  Moisten 
the  bead  with  the  tongue  and  touch  the  finely 
powdered  mineral.  After  reducing,  cool  the 
bead  in  the  inner  cone  of  the  Bunsen  flame  in 
order  to  avoid  oxidation. 

In   Sodium    Metaphosphate   Bead.      The 

bead  is  made  by  heating  sodium  ammonium  phosphate  on  a 
loop  of  platinum  wire  in  the  same  manner  as  previously 
described  for  the  borax  bead;  but  when  first  fused  it  is  much 
more  liquid  than  borax  and  the  greatest  care  must  be  exercised 
in  order  to  avoid  dropping  it.  It  is  best  to  tilt  the  burner  at  a 
considerable  angle  (Fig.  80),  so  that  beads  cannot  drop  into  it 
and  clog  it.  Hold  the  wire  over  the  center  of  the  flame,  with  the 
circular  loop  horizontal.  Do  not  undertake  to  fuse  much  of  the  salt 
at  a  time,  but  build  up  the  bead  by  small  additions,  heating  each 
time  until  all  bubbling  stops.  The  salt  fuses  to  sodium  metaphos- 

*  Sulphides,  arsenides,  antimonides,  etc.,  must  first  be  roasted  thoroughly 
at  a  dull  red  heat  (Fig.  75),  in  order  to  convert  them  into  oxides;  otherwise  no 
characteristic  reaction  will  occur. 

t  A  minute  grain  of  KNOs  added  to  the  hot  bead  after  the  mineral  is  dis- 
solved gives  instant  oxidation. 


FIG.  79 — Platinum 
wire  loops :  (a) 
single  loop  §  inch, 
for  bead  tests; 
(6)  double  loop, 
holding  larger 
quantity,  for  de- 
composing insol- 
uble minerals  in 
fluxes. 


BLOWPIPE  OPERATIONS  AND  CHEMICAL  TESTS 


169 


BORAX  BEAD  REACTIONS 

(For  abbreviations,  see  page  285) 
(M  indicates  medium  amount;   +  indicates  much;    —  indicates  little) 


Oxidizing  Flame. 

Reducing  Flame. 

Amount. 

Oxide  of 

Hot. 

Cold. 

Hot. 

Cold. 

Colorless 

Colorless 

Colorless 

Colorless 

+  or  ,- 

Si,  Al,  Sn 

Colorless 

Cols,  or 
opaq.  wh. 

Colorless 

Cols,  or 
opaqe  wh. 

+  or  - 

Ca,  Sr,  Ba,  Mg, 
Zn,  Zr,  Cb 

Pale  yel. 

Cols,  or  wh. 

Pale  yel 

Colorless 

+ 

Pb,  Sb,  Cd 

Pale  yel. 

Cols,  or  wh. 

Gray 

Gray 

+ 

Bi 

Pale  yel. 

Cols,  or  wh. 

Brown 

Brown 

+ 

Mo 

Pale  yel. 

Cols,  or  wh. 

Yellow 

Yel.  to  yelh- 
brn. 

M 

W 

Pale  yel. 

Cols,  or  wh. 

Grayish 

Bnh.  -violet 

M 

Ti 

Yellow 

Nearly  cols. 

Pale  green 

Nearly  cols. 

- 

Fe,  U 

Yellow 

Yelh.-green 

Green 

Green 

- 

Cr 

Yellow 

Pale     yelh.- 
grn. 

Dirty  grn. 

Fine  green 

- 

V 

Yel.  to  or- 
ange 

Yellow 

Pale  green 

Pale  grn.  to 
nearly  cols. 

Mto  + 

U 

Yel.  to  or- 
ange 

Yellow 

Bottle  grn. 

Pale  green 

Mto  + 

Fe 

Yel.  to  or- 
ange 

Yelh.-grn. 

Green 

Green 

Mto  + 

Cr 

Green 

Blue 

Cols,  to  grn. 

Opaq.    red 

(+) 

-toM 

Cu 

Blue 

Blue 

Blue 

Blue 

-toM 

Co 

Violet 

Rdh.-brn. 

Opaqe  gray 

Opaqe  gray 

-toM 

Ni 

Violet 

Rdh.-violet 

Colorless 

Colorless 

- 

Mn 

170  DETERMINATION   BY  BLOWPIPE  TESTS 

phate,  NaPOs,  and  is  used  in  exactly  the  same  manner  as  the  borax 
bead. 

In  Sodium  Carbonate  (Soda)  Bead.  The  soda  bead  on  plati- 
num wire  is  opaque  white  when  cold.  It  is  prepared  in  the  same 
manner  as  borax  or  s.ph.  beads  (see  preceding  sections),  and  is  useful 
for  the  following  reactions: 

Manganese:  in  o.f.,  green  when  hot,  blue  when  cold;  in  r.f., 
colorless. 

Chromium:  in  o.f.,  yellow. 

Quartz,  chalcedony,  or  opal:  in  fine  powder  fused  with  about 
equal  volume  of  soda  gives  a  clear  glass. 


FIG.  80. — Making  a  bead  in  the  Bunsen  flame.  If  the  bead  drops  it  falls  clear  of 
the  burner  instead  of  clogging  it.  This  position  is  specially  important  for 
sodium  metaphosphate  (s.ph.)  beads.  A  metal  tray  should  be  so  placed  as 
to  catch  the  fused  fluxes  that  drop. 

With  Acids.  For  most  purposes  dilute  hydrochloric  acid  is  used; 
but  for  sulphides  and  arsenides,  which  require  oxidation,  nitric  acid 
is  best. 

Usually  the  object  of  the  first  test  with  an  acid  is  to  determine 
whether  or  not  the  mineral  is  decomposed  or  dissolved  by  it.  This 
is  best  done  as  follows: 

(1)  Using  the  small  blade  of  a  knife  (say  less  than  one-fourth 
inch  wide)  for  a  spatula,  put  into  the  test  tube  as  much  of  the  finely 
pulverized  mineral  (not  lumps  or  grains)  as  will  lie  on  one-half  inch  of 
the  tapering  point.  Pure  homogeneous  material  should  be  used, 
or  allowance  made  for  any  known  impurity. 


BLOWPIPE  OPERATIONS  AND   CHEMICAL  TESTS 


171 


SODIUM  METAPHOSPHATE  BEAD  REACTIONS 

(For 'abbreviations,  see  page  285) 
(M  indicates  medium  amount;   +  indicates  much;    —indicates  little) 


Oxidizing  Flame. 

Reducing  Flame. 

Amount. 

Oxide  of 

Hot. 

Cold. 

Hot. 

Cold. 

Colorless 

Cols,  or 
opaq.  white 

Colorless 

Cols,  or 
opaq.  white 

-or  + 

Ca,  Sr,  Ba,  Mg, 
Zn,    Al,    Zr, 
Sn,     Si     (Si 
nearly  insol.) 

Pale  yel. 

Colorless 

Pale  yel. 

Colorless 

+ 

Cd 

Pale  yel. 

Colorless 

Gray 

Gray 

+ 

Pb,  Sb,  Bi 

Pale  yel. 

Colorless 

Brown 

Brown 

+ 

Cb 

Pale  yel. 

Colorless 

Dirty  blue 

Fine  blue 

M 

W 

Pale  yel. 

Colorless 

Yellow 

Violet 

-to  + 

Ti 

Yellow 

Colorless 

Pale     yelh.- 
grn. 

Colorless 

- 

Fe 

Yellow 

Pale     grnh.- 

yel. 

Pale  grn. 

Fine  grn. 

M 

u 

Yelh.-grn. 

Colorless 

Dirty  grn. 

Fine  grn. 

M 

Mo 

Yel.  to 
bnh.-red 

Yel.  to  cols. 

Red,  yel.,  to 
yelh.-grn. 

Nearly  cols, 
to  pale  vio- 
let 

Mto  + 

Fe 

Yel.  to 
deep  yel. 

Yellow 

Dirty  grn. 

Fine  grn. 

-toM 

V 

Red  to 
bnh.-red 

Yel.  to 

redh.-yel. 

Red  to 
bnh.-red 

Yel  to 
redh.-yel. 

-toM 

Ni 

Green 

Pale  blue 

Pale  yelh.- 
grn. 

Pale  blue, 
nearly 
cols.  ;    at 
times  ruby 
red 

Cu 

Dark  green 

Blue 

Bnh.-grn. 

Opaq.  red 

M 

Cu 

Dirty  grn. 

Fine  grn. 

Dirty  grn. 

Fine  grn. 

-toM 

Cr 

Blue 

Blue 

Blue 

Blue 

-  toM 

Co 

Gryh.-violet 

Violet 

Colorless 

Colorless 

M 

Mn 

172  DETERMINATION  BY  BLOWPIPE  TESTS 

(2)  Add  acid  (dilute  HC1  unless  otherwise  specified)  to  a  depth 
of  one-half  to  three-quarters  of  an  inch. 

(3)  Shake  up  the  powder  in  the  acid  and  note  carefully  its  behavior 
— how  much  it  roils  the  liquid  and  how  slowly  or  rapidly  it  settles 
out  and  clears. 

(4)  If  no  immediate  reaction  occurs  in  the  cold  acid,  heat  to  the 
boiling  point  over  the  Bunsen  flame  *  and  note  any  change,  partic- 
ularly whether  any  of  the  mineral  powder  has  disappeared. 

(5)  If  the  mineral  seems  unchanged  continue  the  boiling  until 
two-thirds  of  the  acid  has  been  evaporated. 

(6)  If  the  result  still  seems  to  be  negative,  filter  the  acid  into  a 
clean  test  tube  and  evaporate  to  dryness.    The  residue,  if  any,  is 
the  measure  of  the  reaction  that  has  taken  place. 

(7)  If  solution  or  other  reaction  occurs  the  results  should  be  care- 
fully noted,  as  follows: 

(a)  Solution  with  effervescence  in  cold  acid,  or  only  on  heating 
(and  this  point  should  be  carefully  observed),  with  the  evolution  of 
CC>2,  colorless  and  odorless,  from  carbonates  (test  with  Ba(OH)2  on 
glass  rod);  EbS,  colorless  and  disagreeable  odor,  from  some  sul- 
phides; Cl,  nearly  colorless,  pungent  odor  (bleaches  moist  litmus 
paper),  from  some  higher  oxides  in  HC1;  NO2,  dark  red  vapors, 
from  oxidation  of  sulphides,  etc.,  in  HNOs. 

(6)  Solution  without  effervescence,  giving  a  clear  colorless  solution, 
without  residue.  When  slow  this  reaction  is  sometimes  difficult  to 
detect.  Filtration  and  evaporation  to  dryness  may  be  resorted  to 
in  case  of  doubt,  or  a  drop  of  perfectly  clear  liquid,  after  settling, 
may  be  removed  with  a  pipette  and  evaporated  on  a  watch  glass,  a 
piece  of  platinum  foil,  or  a  flake  of  mica.  A  residue  shows  that  some 
solution  has  taken  place. 

(c)  Solution  may  occur  without  effervescence  and  without  resi- 
due, as  described  in  the  preceding  paragraph,  but  with  a  colored 
solution — yellowish  to  brownish  red  from  ferric  iron  minerals  in  HC1; 
green  from  nickel  and  from  mixtures  of  copper  and  iron  (add  ammonia 
and  the  solution  becomes  blue  with  copper  or  nickel,  more  intense 
with  copper) ;  blue  from  copper  minerals,  intensified  by  the  addition 
of  an  excess  of  ammonia;  pink  or  pale  rose  from  cobalt  minerals. 

(d)  Solution  may  occur  without  effervescence,  leaving  an  insol- 
uble residue — gelatinous  silica,  from  some  silicates,  appears  on  evapora- 

*  An  alcohol  lamp  is  a  good  substitute,  and  an  ordinary  kerosene  lamp 
serves  very  well  if  the  tube  is  held  in  the  top  of  the  chimney.  A  test  tube 
may  be  even  heated  over  a  candle  flame  by  holding  it  just  high  enough  to 
avoid  blackening  it  with  soot. 


BLOWPIPE  OPERATIONS  AND  CHEMICAL  TESTS          173 

tion  of  the  acid  and  remains  insoluble  when  diluted  with  water  or 
more  acid;  powdery  or  flaky  silica  separates  from  some  silicates — it 
is  white  and  more  translucent  than  the  fine  powder  of  the  mineral; 
white  opaque  metallic  oxides,  especially  from  tin,  antimony,  and  lead 
minerals  hi  HN03;  yellow  powder,  WOs,  from  some  tungstates  in 
HC1;  yellow  floating  mass  of  sulphur,  often  black  with  particles  of 
the  mineral,  from  many  sulphides  in  HNOs. 

With  Cobalt  Nitrate.  The  solution  is  useful  with  light-colored 
infusible  minerals.  Heat  a  small  amount  of  the  fine  powder  or 
minute  fragments  intensely  on  charcoal  in  the  oxidizing  flame; 
moisten  the  mineral  with  the  solution,  and  again  ignite  to  an  intense 
white  heat.  Distinct  colors  may  be  imparted,  as  follows: 

Blue,  aluminum  minerals,  zinc  silicates. 

Bluish  green,  tin  oxide. 

Yellowish  green,  zinc  and  titanium  oxides. 

Dark  green,  oxides  of  antimony  and  cobalt. 

Pink,  usually  pale,  from  magnesium  minerals. 

Calcite  and  aragonite  are  readily  distinguished  by  reaction  with 
Co(N03)2  solution.  Place  fine  powder  of  calcite  and  the  mineral  to 
be  tested  in  separate  test  tubes,  fill  each  about  one-half  inch  deep 
with  the  solution,  and  boil  both  together  by  holding  the  tubes  side 
by  side  over  the  Bunsen  flame.  Aragonite  is  colored  a  deep  lavender 
by  CoCOs  while  calcite  remains  white,  except  on  long  continued 
boiling. 

Precipitates  from  Solution.  The  following  reagents  are  most 
commonly  used.  For  distinctions  between  the  various  precipitates, 
see  the  tests  for  the  elements  on  succeeding  pages. 

Ammonia  precipitates  hydroxides  of  Al,  Gl,  Bi,  chromic  Cr,  Fe, 
Pb,  Ti,  and  rare  earth  metals.  (In  the  presence  of  phosphoric, 
arsenic,  silicic,  and  hydrofluoric  acids  various  other  substances  are 
also  precipitated.) 

Ammonium  carbonate  and  ammonium  oxalate  precipitate  Ca,  Sr, 
and  Ba  from  solutions  made  alkaline  with  ammonia. 

Ammonium  sulphide  precipitates  from  neutral  or  alkaline  solu- 
tions sulphides  of  Fe,  Zn,  Mn,  Co,  Ni,  and  hydroxides  of  Al,  Cr,  and 
rare  earth  metals. 

Barium  chloride  precipitates  BaSC>4  from  acid  solutions  of  a  sul- 
phate— a  delicate  test. 

Hydrochloric  acid  precipitates  chlorides  of  Ag,  Pb,  and  mercurous 
Hg  from  solutions  in  HNO3. 

Silver  nitrate  precipitates  silver  chloride,  bromide,  or  iodide  from 
solutions  of  the  corresponding  minerals  in  water  or 


174  DETERMINATION  BY  BLOWPIPE  TESTS 

Sodium  phosphate  precipitates  Mg  from  solutions  in  which 
ammonia  and  ammonium  carbonate  give  no  precipitates  or  in  the 
filtrate  after  precipitating  with  these  reagents. 

Sulphuric  acid  precipitates  sulphates  of  Pb,  Ba,  and  Sr,  and  also 
Ca  in  concentrated  solutions. 


REACTIONS  FOR  THE  ELEMENTS 

(For  list  of  elements,  see  page  286,  abbreviations,  page  285) 

ALUMINUM  (Al;  trivalent;  at.wt.  27.1) 

(1)  Color  with  Cobalt  Nitrate.    Fine  powder  of  light-colored 
infus.  Al  minerals  assume  a  fine  blue  color  when  moistened  with  the 
solution  and  intensely  heated  either  on  ch.  or  in  a  small  loop  of  Pt 
wire.     Zn  silicates  also  give  blue  color,  but  will  yield  test  for  Zn. 

(2)  Precipitation  with  Ammonia.    Added  in  slight  excess  to  acid 
solutions,  gelatinous  A1(OH)3  is  precipitated.     To  distinguish  from 
other  similar-looking  precipitates  obtained  in  the  same  way,  filter, 
wash  the  ppt.,  place  part  of  it  in  test  tube  with  H2O  and  KOH;  if  it 
is  Al(OH)s  it  will  go  easily  into  solution.     Burn  the  filter  (in  crucible 
or  on  ch.)  and  the  rest  of  the  ppt.  will  give  foregoing  test  with  cobalt 
nitrate. 

For  Al  in  silicates,  see  Silicon  (2),  page  185. 

ANTIMONY  (Sb;  trivalent  and  pentavalent;  at.wt.  120.2) 

(1)  Oxide  Subl.  on  ch.     Heat  fragments  on  ch.  in  o.f.     A  dense 
white  subl.  of  Sb2Os  forms  very  near  the  assay  (compare  As).     Where 
thin  the  coating  looks  bluish.     Subl.  is  volatile  and  may  be  driven 
about  readily  by  the  o.f.  or  r.f.     No  distinctive  odor  (compare  As) 
unless  S  or  As  is  present. 

(2)  Antimonate  Subl.  in  o.t.    When  heated  in  o.t.  most  Sb  sul- 
phides yield  a  heavy  white  subl.,  SbSb04,  along  the  under  side  of  the 
tube,  which   is    non-vol.  (compare  As),  straw-yel.  when  hot  and 
white  on  cooling. 

(3)  Oxysulphide  Subl.  in  c.t.     On  intense  ign.  sulphides  yield  a 
black  subl.  of  Sb2S2O,  rich  redh.-brn.  on  cooling.     Volatilizes  with 
difficulty. 

(4)  Iodide  Subl.  on  Plaster.     Mixed  with  von  Kobell's  flux  or 
moistened  with  HI  and  heated  in  o.f.  on  plaster  tablet,  a  red  subl.  of 

,  which  disappears  in  fumes  of  strong  ammonia. 


REACTIONS  FOR  THE  ELEMENTS  175 

(5)  Flame  Color.  Sb  volatilizes  in  r.f.  and  gives  a  pale  greenish 
color  to  the  flame.  Pt  forceps  must  not  be  used. 

ARSENIC  (As;  trivalent  and  pentavalent;  at.wt.  75) 

(1)  Oxide  Subl.  on  ch.    Metallic  As,  its  sulphides  and  the  arsen- 
ides when  heated  on  ch.  yield  white  fumes  of  a  garlic-like  odor  and  a 
white  crystalline  subl.  of  As2Os  far  from  the  assay. 

(2)  Oxide  Subl.  in  o.t.    Subl.  and  odor  like  preceding  are  pro- 
duced in  the  tube.     Easily  volatile  and  driven  out  of  the  tube. 

(3)  Metallic  Mirror  in  c.t.     The  metal  and  some  arsenides  yield 
a  brilliant  black  arsenical  mirror.     When  abundant  the  part  nearest 
the  assay  crystallizes  and  looks  gray.     By  breaking  off  the  closed 
end  of  tube  and  heating  the  subl.    the  garlic  odor  is  produced. 
Oxygen  compounds  require  powdered  charcoal  also  in  the  c.t. 

(4)  Iodide  Subl.  on  Plaster.     Powder  mixed  with  von  KobelPs 
flux  or  moistened  with  HI  and  heated  in  o.f.  on  plaster  tablet,  a  vol. 
orange-yel.  subl.  of  Asls  forms. 

(5)  Flame  Color.     In  r.f.  As  volatilizes  and  colors  the  flame  violet. 

BARIUM  (Ba;  bivalent;  at.wt.  137.4) 

(1)  Flame  Color.    A  gnh.-yel.  color  is  imparted  to  the  flame, 
sometimes  intensified  by  moistening  with  HC1.     Silicates  do  not 
give  the  flame  color.     Must  be  distinguished  carefully  from  B, 
MnCls,  and  P  flame  colors. 

(2)  Sulphate  Precipitate.     A  few  drops  of  dilute  H2SO4  give  a 
white  ppt.  of  BaS04  from  solutions  in  water  and  dilute  acids.     A 
delicate  test  and  distinguishes  from  B  and  P.     Insoluble  silicates 
require  previous  fusion  of  the  finely  powdered  mineral  with  3  vol- 
umes of  soda  in  a  loop  of  Pt  wire,  which  renders  them  soluble  in 
HC1.     Test  ppt.  for  flame  color  using  clean  Pt  wire.     If  both  Ba  and 
Sr  are  present  a  mixed  flame  results. 

(3)  Alkaline  Reaction.    Like  the  other  alkaline  earths  and  most 
alkalis,  some  Ba  minerals  give  alkaline  reaction  on  moist  turmeric 
paper  after  ignition. 

BISMUTH  (Bi;  trivalent;  at.wt.  208) 

(1)  Metallic  Bi  and  Oxide  Subl.  on  ch.  Heat  the  mineral  with 
3  times  its  volume  of  soda  on  ch.  Brittle  metallic  globules  of  Bi  are 
obtained  and  a  yellow  coating  of  Bi2Os  which  is  white  further  away. 


176  DETERMINATION  BY  BLOWPIPE  TESTS 

Subl.  much  like  that  of  Pb,  but  metal  less  malleable;   distinguished 
by  the  following  test. 

(2)  Iodide  Ppt.  on  ch.  and  Plaster.  Mix  the  powdered  mineral 
with  von  Kobell's  flux  or  moisten  with  HI  and  heat  in  the  o.f.  on  ch. 
The  subl.  is  yellow  near  the  assay  and  bordered  by  brilliant  red  Bils. 
On  a  plaster  plate  the  subl.  is  chocolate-brown  but  changes  to  a  bril- 
liant red  on  exposure  to  strong  ammonia  fumes. 

BORON  (B;  trivalent;  at.wt.  11) 

(1)  Flame  Color.     A  somewhat  yellowish-green   (siskin-green) 
flame  color.     Compare  Ba  and  MnCla  flame  colors.     Readily  dis- 
tinguished by  other  tests.     Some  B  minerals  require  heating  with 
3  volumes  of  Turner's  flux;    the  BF2  formed  gives  a  momentary 
color  to  the  flame. 

(2)  With   Turmeric   Paper.    Moisten   turmeric   paper   with   a 
dilute  HC1  sol.  of  the  mineral  and  dry  it  on  the  outside  of  a  test  tube 
containing  boiling  water.     The  paper  becomes  reddish-bro\\n;    on 
moistening  with  ammonia  it  becomes  black.     Insol.  minerals  must 
first  be  fused  in  fine  powder  with  3  volumes  of  soda  on  a  loop  of  Pt 
wire  and  then  dissolved  in  HC1. 

BROMINE  (Br;  univalent;  at.wt.  79.9) 

(1)  Precipitation  as  Bromide.     Solutions  of  bromides  in  water  or 
dilute  HNOs  yield  a  white  ppt.  of  AgBr  when  AgNOs  sol.  is  added. 

(2)  Pb  Bromide  Subl.  in  c.t.    AgBr  heated  in  c.t.  with  galena 
(PbS)  yields  a  subl.  of  PbBr2,  which  is  S-yellow  while  hot  and  white 
when  cold. 

CADMIUM  (Cd;  bivalent;  at.wt.  112.4) 

(1)  Oxide  Subl.  on  ch.  Heated  on  ch.  with  3  volumes  of  soda, 
metallic  Cd  is  volatilized  and  sublimed  as  reddish-brown  CdO,  which 
is  yellow  dietant  from  the  assay  and  iridescent  if  only  a  little  forms. 

CALCIUM  (Ca;  bivalent;  at.wt.  40.1) 

(1)  Flame  Color.  Some  Ca  minerals  give  yelh.-red  color  to  the 
flame  (green  through  green  glass),  often  strengthened  by  moistening 
with  HC1.  Must  not  be  confused  with  the  much  redder  Sr  and  Li 
flames. 


REACTIONS  FOR  THE  ELEMENTS  177 

(2)  Sulphate  ppt.     A  few  drops  of  dilute  H2SO4  added  to  an  HC1 
sol.  of  a  Ca  mineral  precipitates  white  CaSO4  •  2H2O,  which  goes  into 
solution  on  addition  of  water  and  boiling.     This  sol.  in  water  dis- 
tinguishes it  from  Sr  and  Ba. 

(3)  Carbonate  or  Oxalate  ppt.    Ammonium  carbonate  or  oxalate 
added  to  a  solution  made  strongly  alkaline  with  ammonia  forms  a 
white  ppt.  of  the  corresponding  Ca  compound.     The  oxalate  is  also 
formed  in  slightly  acid  solutions  and  this  test  can  be  applied  in  solu- 
tions of  phosphates,  silicates,  and  borates,  which  cannot  be  made 
alkaline  with  ammonia  without  precipitating  Ca  salts. 

(4)  Alkaline  Reaction.     Like  other  alkaline  earths  and  most  of 
the  alkalis,  some  Ca  minerals  give  an  alkaline  reaction  on  moist 
turmeric  paper  after  ignition. 

For  Ca  in  silicates,  see  Silicon  (2),  page  185. 

CARBON  (C;  tetravalent;  at.wt.  12) 

(1)  Odor  in  c.t.     The  characteristic  empyreumatic  odor  of  dis- 
tilling organic  substances  is  given  in  c.t.  by  hydrocarbons  and  bitu- 
minous coal.     Anthracite  does  not  yield  it,  but  is  combustible  in 
the  o.f. 

(2)  CO2  from  Carbonates.    Heat  fragments  of  the  mineral  in 
the  c.t.  held  horizontally  with  a  drop  of  Ba(OH)2  in  the  open  end  of 
the  tube;  the  latter  is  clouded  .with  a  white  ppt.  of  BaCOs. 

(3)  Effervescence  with  Acids.    Treat  the  powdered  mineral  with 
dilute  HC1,  HNOs,  or  H2SO4,  and  warm  if  necessary.     Guard  against 
mistaking  boiling  for  effervescence.     Tip  the  test  tube  gently  and 
pour  accumulated  C02  (gas)  into  another  tube  containing  Ba(OH)2; 
on  shaking  the  latter  a  white  ppt.  of  BaCOs  forms.     Concentrated 
acids  do  not  yield  the  test  unless  the  salts  formed  are  soluble  in  the 
acids. 

CHLORINE  (Cl;  univalent;  at.wt.  35.5) 

(1)  Flame  Color  with  CuO.     Mix  powdered  mineral  with  CuO 
and  moisten  with  H2SO4,  dry  gently  on  ch.  and  ignite;   or  saturate 
a  small  s.ph.  bead  with  CuO,  add  a  fragment  of  the  mineral  and  heat 
in  the  o.f.     In  either  case  the  azure-blue  flame  of  CuCl2  will  appear. 
Br  gives  a  similar  reaction. 

(2)  Evolution  of  Cl.    A  powdered  chloride  heated  in  a  small  test 
tube  with  a  little  pyrolusite  (MnO2)  and  4  times  its  volume  of  KHSO4 
gives  off  Cl  gas,  which  is  recognized  by  its  pungent  odor  and  its  bleach- 


178  DETERMINATION  BY  BLOWPIPE  TESTS 

ing  effect  on  a  piece  of  moist  litmus  paper  placed  inside  the  tube. 
AgCl  and  silicates  containing  Cl  require  fusion  first  with  3  volumes 
of  soda. 

(3)  AgCl  ppt.    From  a  solution  pf  a  chloride  in  water  or  dilute 
HNOs  a  few  drops  of  AgNOs  sol.  ppts.  white  AgCl,  curdy  if  abun- 
dant, bluish  opalescent  if  little.     Br  and  I  give  similar  reactions. 
Light  soon  changes  color  of  the  ppt.  .to  violet.     Insoluble  minerals 
must  first  be  fused  with  3  volumes  of  soda. 

(4)  Sublimate  with  Galena.    To  distinguish  chloride,  bromide, 
and  iodide  of  Ag,  heat  in  c.t.  with  powdered  galena.     A  subl.  of 
PbCl2  forms  colorless  globules  which  are  white  when  cold;  PbBr2  is 
S.-yel.  hot  and  white  when  cold;   PbI2  is  dark  orange-red  hot  and 
lemon-yellow  cold.     The  presence  of  Br  obscures  that  of  Cl,  and  I 
obscures  both  of  the  others. 

CHROMIUM  (Cr;  trivalent  and  sexivalent;  at.wt.  52)  • 

(1)  Borax  Bead  Reac.     In  o.f.  yellow  hot   (red  with  much), 
yel.-grn.  cold.     In  r.f.  green  hot  and  cold. 

(2)  S.ph.  Bead  Reac.     In  o.f.  dirty  green  hot,  clear  green  cold. 
In  r.f.  similar  colors  but  weaker.     V  differs  in  giving  yellow  color  to 
s.ph.  bead  in  o.f. 

(3)  Soda  Bead  Reac.    In  o.f.  dark  yellow  while  hot,  light  yellow 
and  opaque  cold;  in  r.f.  yelh.-green  opaque  when  cold. 

COBALT  (Co;  bivalent;  at.wt.  59) 

(1)  In  Borax  and  s.ph.  Beads.  Fine  blue  in  both  o.f.  and  r.f. 
When  Cu  or  Ni  interferes  remove  the  bead  from  the  Pt  wire  and  fuse 
it  on  ch.  with  a  granule  of  Sn  and  the  Co  color  will  appear. 

COLUMBIUM  (Niobium)  (Cb;  pentavalent;  at.wt.  93.5) 

(1)  Reduction  in  Solution.  Mix  powdered  mineral  with  5 
volumes  of  borax,  moisten  to  a  paste  with  water  and  fuse  in  a  double 
loop  of  Pt  wire  (Fig.  796).  Crush  2  or  3  such  beads  to  powder  arid 
boil  with  HC1  to  a  clear  solution.  Add  Sn  and  boil  and  the  sol. 
becomes  blue,  which  changes  slowly  to  brown  on  continued  boiling 
and  disappears  on  dilution.  With  Zn  instead  of  Sn  the  blue  color 
changes  quickly  to  brown.  W  gives  similar  tests,  but  other  tests  for 
that  element  will  distinguish. 


REACTIONS  FOR  THE  ELEMENTS  179 


COPPER  (Cu;  bivalent  and  univalent;  at.wt.  63.6) 

(1)  Flame  Color.    The  oxide  and  oxidized  sulphides  give  an 
emerald-green  color.     When  moistened  with  HC1  the  flame  is  azure- 
blue.     The  same  result  is  obtained  by  adding  a  grain  of  common 
salt,  NaCl,  to  a  s.ph.  bead  saturated  with  the  substance. 

(2)  Metallic  Cu  on  ch.     Oxides  and  sulphides  that  have  been 
previously  roasted  yield  globules  of  red  malleable  Cu  when  fused  in 
r.f .  on  ch.  with  3  volumes  of  a  flux  of  equal  parts  of  soda  and  borax. 

(3)  Borax  and  s.ph.  Bead  Reactions.    In  o.f.  green  hot  and  blue 
cold;  in  r.f.  pale  with  little  Cu,  red  and  opaque  with  much. 

A  ruby  red  transparent  bead  is  obtained  by  adding  a  little  tin  or 
tin-bearing  substance  to  a  borax  bead  made  pale  blue  with  Cu  in  o.f. 
Dissolve  thoroughly  in  o.f.  and  reduce  slightly.  If  too  much  reduced 
the  bead  is  colorless.  A  delicate  test  for  either  Cu  or  Sn. 

(4)  Color  in  Solution.    Blue  or  green  sol.  in  HNO3  or  HC1  made 
deep  blue  by  adding  ammonia  in  excess.     Ni  gives  a  much  fainter 
blue  by  similar  treatment. 

(5)  Cuprous  Cu.     Dissolve  mineral  in  a  little  HC1  and  add  water. 
A  white  ppt.  of  cuprous  chloride  (CuCl)  appears. 

FLUORINE  (F;  univalent;  at.wt.  19) 

(1)  HF  in  c.t.    Mix  the  finely  powdered  mineral  with  an  equal 
volume  of  powdered  glass  and  3  volumes  of  KHSCU  and  heat  gently 
in  c.t.     The  HF  liberated  attacks  the  glass  and  forms  SiF/i,  which 
decomposes  to  H^SiFe  with  separation  of  SiO2j  this  forms  a  volatile 
white  subl.  in  the  tube.     Break  off  bottom  of  tube,  wash  subl.  with 
water  and  dry;  the  remaining  subl.,  SiOa,  is  non-vol. 

(2)  Etching  Glass.     Mix  powdered  mineral  with  a  few  drops  of 
cone.  H2&O4  and  spread  over  a  glass  that  has  been  previously  coated 
with  paraffin  and  scratched  with  a  pointed  instrument.     Let  stand 
5  minutes  or  longer.     Wash  off  the  acid,  warm  the  glass,  and  wipe 
off  paraffin  to  observe  etching. 

(3)  With  NaPOs  in  c.t.     Mix  the  powdered  mineral  with  5  times 
the  volume  of  powdered  s.ph.  beads  and  heat  very  hot  hi  c.t.     A  subl. 
forms  as  in  (1)  and  may  be  tested  as  there  described. 

GOLD  (Au;  univalent  and  trivalent;  at.wt.  197.2) 

(1)  Metal  with  Soda  on  ch.  The  color,  fusibility,  malleability, 
and  insolubility  in  any  single  acid  serve  to  distinguish  it  from  other 
metals  when  present  in  visible  particles. 


180  DETERMINATION  BY  BLOWPIPE  TESTS 

(2)  Purple  of  Cassius.  Carefully  evaporate  the  solution  in  aqua 
regia  to  dryness,  add  a  little  water  and  dilute  solution  of  stannous 
chloride  (SnCl2).  The  purple  ppt.  of  colloidal  Au  and  Sn(OH)2  are 
soluble  in  ammonia  to  a  reddish  liquid. 

HYDROGEN  (H;  univalent;  at.wt.  1) 

(1)  Water  in  c.t.  Minerals  containing  hydroxyl,  acid  hydrogen, 
or  water  of  crystallization,  when  heated  in  c.t.  give  off  water  which 
condenses  in  the  cold  part  of  the  tube.  Hydroxyl  and  acid  H  require 
high  temperature.  Some  salts  of  weak  bases  yield  acid  water  and 
from  some  ammonia  compounds  it  is  alkaline.  Readily  tested  by  a 
strip  of  litmus  paper  inserted  in  the  tube. 

IODINE  (I;  univalent;  at.wt.  126.9) 

(1)  Iodide  Subl.  with  Galena.    Heat  the  powdered  mineral  with 
powdered  galena  in  c.t.;    a  subl.  of  Pbl2  is  formed  which  is  dark 
orange-red  while  hot  and  lemon-yellow  when  cold. 

(2)  Ppt.  with  AgNO3.    From  dil.  HN03  solution  AgNO3  ppts. 
white  Agl,  which  differs  from  AgCl  and  AgBr  in  being  nearly  insol- 
uble in  ammonia. 

(3)  I  with  KHSQ4.    Violet  I  vapor  is  formed  when  iodides  are 
heated  in  c.t.  with  KHSO4. 

IRIDIUM  (Ir;  trivalent  and  tetravalent;  at.wt.  193.1) 
One  of  the  rare  Pt  metals.     See  Platinum,  page  184. 

IRON  (Fe;  bivalent  and  trivalent;  at.wt.  55.8) 

(1)  Magnetism.    A  few  Fe  minerals  are  magnetic  and  many 
become  so  on  heating  in  r.f.  (or  roasting  and  then  heating  in  r.f.  in 
case  of  sulphides  and  arsenides).     The  test  is  more  delicate  if  the 
powder  is  fused  with  a  little  soda,  giving  a  magnetic  slag.     In  all 
cases  only  the  cold  material  is  magnetic. 

(2)  Borax  Bead  Reac.     With  small  amount  of  mineral  the  bead 
in  o.f.  is  yellow  hot  and  nearly  colorless  cold;  in  r.f.  it  becomes  pale 
green  hot  and  colorless  cold.    With  much  of  the  mineral  it  is  bnh.- 
red  hot  and  yellow  cold;  in  r.f.  it  becomes  bottle-green  hot  and  paler 
when  cold.     With  sulphides  and  arsenides  the  bead  test  can  be  made 
only  after  roasting. 

(3)  Hydroxide  ppt.     When  ammonia  is  added  to  a  dil.  HNOs 
sol.  or  to  HC1  sol.  which  has  been  boiled  with  a  few  drops  of  HNOs, 


REACTIONS  FOR  THE  ELEMENTS  181 

a  bnh.-red  ppt.  of  Fe(OH)3  is  formed.  In  ferrous  HC1  sol.  ammonia 
gives  a  dirty  green  Fe(OH)2  ppt.  which  slowly  turns  brown  by  oxida- 
tion. 

(4)  Ferrous  and  Ferric  Fe.  In  cold  dilute  acid  solutions  potas- 
sium ferri cyanide,  KeFe2(CN)i2,  gives  a  dark  blue  ppt.  with  ferrous 
Fe;  in  ferric  solutions  it  deepens  the  color  but  gives  no  ppt.  Potas- 
sium ferrocyanide,  K4Fe(CN)4,  gives  a  dark  blue  ppt.  with  ferric 
solutions;  from  ferrous  sol.  it  gives  a  pale  bluish-white  ppt.  which 
rapidly  becomes  blue.  NH4CNS  or  KCNS  gives  a  dark  red  color 
to  ferric  solutions. 

Minerals  insol.  in  acids  must  first  be  fused  in  c.t.  with  3  volumes 
of  borax  glass  (powdered  borax  beads).  Break  off  lower  end  of  tube 
and  boil  in  a  little  HC1  for  a  minute;  dilute  the  sol.,  divide  it  into 
two  parts,  and  test  as  above  for  ferrous  and  ferric  Fe. 

For  Fe  in  silicates,  see  Silicon  (2),  page  185. 

LEAD  (Pb;  bivalent  and  tetravalent;  at.wt.  207.1) 

(1)  Metal  and  Subl.  on  ch.     Mix   1   part  powdered  mineral, 
1  part  powdered  charcoal,  and  3  parts  soda,  moisten  and  fuse  in  r.f. 
on  ch.     Globules  of  soft,  malleable,  and  sectile  metal  form,  bright 
in  r.f.  and  dull  on  cooling;    also  subl.  of  PbO,  yellow  near  assay, 
bluish-white  further  away. 

(2)  Iodide  Subl.  on  ch.    Heat  powdered  mineral  with  3  volumes 
of  von  Kobell's  flux  in  o.f.  on  ch.     A  chrome-yel.  subl.  of  Pbl2  forms 
near  and  greenish-yellow  far  from  assay. 

(3)  Ppts.  from  Solution.    From  solution  in  dil.   HNO3  either 
H2SO4  or  HC1  forms  a  white  ppt.  (PbSO4  or  PbCl2).     From  a  boiling 
solution  of  the  mineral  in  HC1  white  PbCl2  crystallizes  out  on  cooling. 

LITHIUM  (Li;  univalent;  at.wt.  6.9) 

(1)  Flame  Color.  Crimson  flame  when  heated  in  Pt  forceps  or 
from  powdered  mineral  on  clean  Pt  wire  (invisible  through  green 
glass).  For  silicates  better  results  are  obtained  by  mixing  the 
mineral  with  equal  parts  of  powdered  gypsum.  Flame  color  is  much 
like  that  of  Sr,  but  redder  than  that  of  Ca.  Compare  Sr  and  Ca. 

MAGNESIUM  (Mg;  bivalent;  at.wt.  24.3) 

(1)  Color  with  Cobalt  Nitrate.  Some  light-colored  Mg  minerals 
become  pale  pink  when  strongly  ignited  after  moistening  with 
Co(NO3)2  sol. 


182  DETERMINATION   BY  BLOWPIPE  TESTS 

(2)  Alkaline  Reac.     Some  Mg  minerals  give  alkaline  reac.  on 
moist  turmeric  paper  after  ignition,  like  the  alkalis  and  alkaline 
earths,  but  weaker,  and  less  decisive. 

(3)  Ppt.  from  Solution.     Use  HNO3  sol.  or  HC1  sol.  that  has 
been  boiled  with  a  drop  of  nitric  acid,  make  strongly  alkaline  with 
ammonia,  and  remove  Fe,  Al,  and  Ca  by  successive  precipitation 
with  ammonia  and  ammonium  oxalate,  filtering  each  time  a  precipi- 
tate appears.     To  the   clear  filtrate   add  sodium   phosphate.     A 
crystalline  ppt.  of  NH4MgPO4  •  6H2O  appears. 

For  Mg  in  silicates,  see  Silicon  (2),  page  185. 

MANGANESE  (Mn;  bivalent,  trivalent,  tetravalent;  at.wt.  54.9) 

(1)  Soda  Bead  Reac.     In  o.f.  green  while  hot,  bluish-green  cold; 
in  r.f.  white. 

(2)  Borax  Bead  Reac.     In  o.f.  opaque  while  hot,  reddish-violet 
when  cold,  black  if  too  much  is  used.     In  r.f.  colorless.     Similar 
results  in  s.ph.  but  not  so  delicate. 

(3)  Evolution  of  Cl.     Higher  oxides  of  Mn  decompose  HC1  with 
evolution  of  Cl  gas. 

(4)  Flame  Color.    HC1  solution  gives  yellowish  green  color  to 
flame.     Compare  Ba  and  B  flames.     (See  p.  161.) 

MERCURY  (Hg;  univalent  and  bivalent;  at.wt.  200) 

(1)  Metal  in  c.t.     Mix  the  powdered  mineral  with  4  volumes  of 
soda  that  has  been  dried  by  heating  nearly  to  redness  on  clean  metal 
or  in  a  porcelain  crucible;  put  mixture  in  c.t.,  cover  with  dry  soda, 
and  heat  gradually.     Hg  appears  as  gray  subl.  or  as  globules  on  the 
walls  of  the  tube.     Alone  in  c.t.  most  Hg  compounds  volatilize  with- 
out decomposing.     Cinnabar  gives  a  black  subl.  like  the  As  mirror. 

(2)  Hg  Ppt.  on  Cu.     Clean  Cu  in  a  Hg  sol.  receives  a  coating  of 
metallic  Hg,  giving  the  appearance  of  silver  plating. 

MOLYBDENUM  (Mo;  tetravalent  and  sexivalent;  at.wt.  96) 

(1)  Subl.  in  o.t.     Thin  flakes  of  molybdenite  at  a  high  tempera- 
ture in  o.t.  give  a  yellow  subl.  of  MoOs,  frequently  also  delicate 
crystals. 

(2)  Flame  Color.    At  tip  of  blue  flame  gives  a  pale  yelh. -green 
color. 

(3)  S.ph.  Bead  Reac.    With  a  small  amount  of  the  oxide  in  o.f. 


REACTIONS  FOR  THE  ELEMENTS  183 

the  bead  is  yelh.-green  while  hot,  nearly  colorless  cold;  in  r.f.  dirty 
green  hot,  fine  green  on  cooling. 

(4)  Color  in  Sol.  Place  finely  powdered  mineral  with  a  minute 
scrap  of  paper  (about  1  mm.  square)  hi  a  test  tube  with  a  few  drops 
of  water  and  an  equal  quantity  of  cone.  H2SO4)  heat  till  copious 
acid  fumes  form,  let  cool,  and  add  water,  one  drop  at  a  time.  A  deep 
blue  color  appears  and  quickly  disappears  with  much  dilution. 

NICKEL  (Ni;  bivalent;  at.wt.  58.7) 

(1)  Borax  Bead  Reac.    In  o.f.  violet  while  hot,  redh.-brown 
cold;   opaque  by  long  heating  in  r.f.     On  ch.  with  Sn  the  bead  be- 
comes colorless.     Co  in  small  amt.  obscures  the  bead  test  for  Ni. 

(2)  Color  of  Sol.  and  Ppt.     Sol.  in  HNOs  is  apple-green;  becomes 
blue  with  ammonia.     Compare  the  much  deeper  blue  with  Cu  from 
this  treatment. 

(3)  Dimethylglyoxime  Test.     To  a  solution  of  the  mineral  add 
ammonia  in  slight  excess  and  a  few  drops  of  the  reagent.     A  scarlet 
crystalline  ppt.  forms.     If  very  little  Ni  is  present,  boil,  and  red 
needles  form  on  cooling.     A  very  delicate  test. 

NITROGEN  (N;  trivalent  and  pentavalent;  at.wt.  14) 

(1)  Deflagration  on   ch.    Nitrates   deflagrate    (flash   somewhat 
like  gunpowder)  upon  ignition  on  ch. 

(2)  Fumes  in  c.t.     Heat  mineral  powder  in  c.t.  with  KHSO4. 
NO2  fumes  given  off  are  recognized  by  red  color  on  looking  into  the 
end  of  the  tube. 

OSMIUM  (Os;  bivalent,  tefcravalent,  etc.;  at.wt.  190.9) 
One  of  the  rare  platinum  metals.    See  Platinum,  page  184. 

OXYGEN  (0;  bivalent;  at.wt.  16) 

(1)  O  gas  in  c.t.     Some  higher  oxides  give  off  0  when  he'ated  in 
c.t.     A  glowing  stick  inserted  will  burn  brightly. 

(2)  Cl  Gas  with  HC1.     Some  higher  oxides  decompose  HC1  with 
the  liberation  of  free  Cl,  which  has  a  pungent  odor  and  bleaches  moist 
litmus  paper  inserted  in  the  tube. 

PALLADIUM  (Pd;  bivalent  and  tetravalent;  at.wt.  106.7) 
One  of  the  rare  platinum  metals.     See  Platinum,  page  184. 


184  DETERMINATION  BY  BLOWPIPE  TESTS 

PHOSPHORUS  (P;  pentavalent;  at.wt.  31) 

(1)  Ppt.  with  Ammonium  Molybdate.     Dissolve  the  powdered 
mineral  in  HNOs,  previously  fusing  in  soda  bead  if  insol.     Add  a  few 
drops  of  the  sol.  to  a  test  tube  containing  ammonium  molybdate 
that  has  been  made  acid  with  HNOs  and  let  stand  a  few  minutes; 
a  yellow  ppt.  forms. 

(2)  Flame  Color.    Pale  bluish-green;    moistening  with  H2S04, 
is  required  with  some  minerals. 

PLATINUM  (Pt;  bivalent  and  tetravalent,  at.wt.  195.2) 

(1)  Platinum  is  recognized  by  its  grayish-white  color,  infusibility, 
insolubility  in  any  single  acid,  and  reddish-yellow  solution  in  aqua 
regia.     It  usually  contains  iron  and  traces  of  the  other  metals  of  the 
Platinum  Group,  of  which  the  following  are  the  most  important: 

(2)  Osmium  gives  the  very  penetrating  and  disagreeable  odor 
of  OsO4  when  the  fine  powder  is  heated  in  c.t.  with  NaN03  or  KNO3. 

(3)  Indium  and  Iridosmium  are  hard  (H  =  6-7),  insoluble  even 
in  aqua  regia.     Fusion  with  NaNOs  hi  c.t.  oxidizes  some  Ir;   break 
off  the  lower  end  of  the  tube  and  boil  the  mass  in  aqua  regia.     The 
solution  becomes  deep  red  to  reddish-black. 

(4)  Palladium  has  a  bluish  tarnish,  which  is  removed  and  a 
Pt-like  color  restored  in  r.f.    The  tarnish  is  renewed  by  moderate 
heat  in  o.f. 

POTASSIUM  (K;  univalent;  at.wt.  39.1) 

(1)  Flame  Color.    Pale  violet,  obscured  by  Na;   violet  or  pur- 
plish-red through  blue  glass,  which  eliminates  the  yellow  of  Na.     For 
silicates  mix  with  an  equal  volume  of  powdered  gypsum  and  heat  on 
a  Pt  wire  the  end  of  which  has  been  moistened  to  make  the  powder 
adhere. 

(2)  Alkaline  Reaction.    Some  K  minerals,  like  those  containing 
some  other  alkalis  and  the  alkaline  earths,  give  an  alkaline  reac.  on 
moist  turmeric  paper  after  intense  ignition. 

For  K  hi  silicates,  see  Silicon  (2),  page  185. 

SELENIUM  (Se;  bivalent  and  sexivalent;  at.wt.  79.2) 

(1)  Odor  and  Subl.  on  ch.  Radish-like  odor.  If  abundant, 
brownish  fumes  form  and  a  silvery  SeC>2  coating,  which  may  have  a 
border  of  red  from  admixture  of  Se. 


REACTIONS   FOR  THE  ELEMENTS  185 

(2)  Flame  Color.     The  subl.  obtained  in  (1)  is  volatile  in  r.f. 
and  imparts  a  fine  azure-blue  color  to  the  flame. 

(3)  Subl.  in  o.t.    White  crystalline  SeO2  subl.  reddened  by 
admixture  of  Se;  volatile  and  gives  a  beautiful  blue  color  to  flame  if 
the  end  of  the  tube  is  held  so  that  the  fumes  enter  the  reducing  part 
of  the  Bunsen  flame. 

(4)  Subl.  in  c.t.    Fused  black  globules  of  Se,  the  smallest  deep 
red  to  brown  by  transmitted  light.     Some  white  SeO2  may  form 
above  the  Se. 

SILICON  (Si;  tetravalent;  at.wt.  28.3) 

(1)  Gelatinization.    Many  silicates  are  completely  soluble  in 
acids  and  give  on  continued  boiling  and  evaporation  a  jelly  of  H^SiOa. 
HNOs  is  best,  but  HC1  will  serve  in  most  cases.     All  silicates,  when 
first  fused  with  5  parts  of  soda  and  dissolved  in  dilute  HC1  and  evapo- 
rated, yield  gelatinous  silica.     It  is  convenient  to  use  the  double  loop 
(Fig.  796)  and  prepare  2  or  3  large  beads,  in  order  to  provide  a  suffi- 
cient quantity  for  distinct  reactions.     This  is  especially  important 
in  the  tests  under  the  next  section. 

(2)  Insol.  Residue  in  Acids.     Insol.  silica  in  powdery  form  remains 
after  solution  of  the  bases  of  some  minerals.     In  suspension  it  makes 
the  solution  translucent  and  not  so  white  and  milky  as  the  powder  of 
an  insol.  mineral.     Verify  solution  by  evaporating  a  drop  of  the 
clear  liquid  on  Pt  foil  or  a  watch  glass  (or  a  flake  of  mica  if  HC1  or 
HNOs  is  used)  and  note  considerable  residue  if  solution  has  occurred. 

Evaporate  the  solution  obtained  in  (1)  or  (2)  to  dryness,  moisten 
with  cone.  HC1,  and  heat  to  boiling,  then  add  2  parts  water  and  boil 
again.  The  bases  go  into  sol.  but  the  silica  remains  and  is  removed 
by  filtering.  For  insol.  silicates  first  fuse  with  soda,  as  directed  in 
the  preceding  section. 

Detection  of  Bases  in  Silicates,  (a)  To  the  filtrate  from  the  preceding 
operations  if  not  a  nitric  acid  solution,  add  a  little  HNO3,  heat  to  boiling  and  add 
ammonia  in  slight  excess.  Al  and  Fe  are  precipitated  as  hydroxides,  A1(OH)3 
and  Fe  (OH)3.  If  the  ppt.  is  light  colored  there  is  little  or  no  Fe;  if  it  is^ reddish 
brown  there  is  considerable  Fe  and  further  test  must  be  made  for  Al  as  follows: 
(6)  Filter;  place  the  ppt.  in  a  test  tube  with  a  little  water  and  a  small  fragment 
of  stick  potash  (KOH)  and  boil.  A1(OH)3  goes  into  solution  and  is  separated 
from  insoluble  Fe(OH)3  by  filtering.  Make  the  filtrate  acid  with  HC1,  boil,  and 
add  ammonia  in  excess  to  precipitate  A1(OH)3  again. 

(c)  Heat  filtrate  from  (a)  to  boiling  and  add  a  little  ammonium  oxalate  to 
precipitate  Ca.     Let  stand  ten  minutes  and  filter.     If  filtrate  is  turbid,  pass  it 
repeatedly  through  the  same  filter  till  it  comes  through  clear. 

(d)  Add  to  the  filtrate  from  (c)  a  little  more  ammonium  oxalate  to  make  sure 


186  DETERMINATION  BY  BLOWPIPE  TESTS 

that  all  Ca  has  been  removed.  If  no  ppt.  forms  add  sodium  phosphate  and  strong 
ammonia  to  precipitate  Mg.  It  may  have  to  stand  for  some  time  after  cooling 
before  the  precipitate  forms. 

(e)  If  alkalis  are  to  be  tested  for,  filter  off  the  Mg  ppt.  of  (d),  evaporate  the 
filtrate  to  dryness  and  heat  to  redness  to  drive  off  ammonia  salts.  Test  the 
residue  for  K  and  Na  flame  colors  with  a  Pt  wire. 

(3)  In  s.ph.  Bead.  Silica  dissolves  very  slowly  in  s.ph.,  hence  a 
"  skeleton  "  of  translucent  silica  remains  after  treating  a  powdered 
silicate  in  s.ph.  bead. 

SILVER  (Ag;  univalent;  at.wt.  107.9) 

(1)  Metal  on  ch.    Fuse  powdered  mineral  with  3  volumes  of 
soda  on  ch.;   a  malleable  metal  globule  is  obtained  which  is  bright 
both  in  the  flame  and  after  cooling.     Test  according  to  (2)  below. 
Compounds  with  S,  As,  and  Sb  on  roasting  in  o.f.  on  ch.  yield  Ag 
globule  which  is  brittle  with  Sb. 

(2)  Subl.  on  ch.    When  Pb  and  Sb  are  present  or  have  been  added, 
the  subl.  of  PbO  and  Sb20s  on  ch.  is  colored  reddish  to  deep  lilac 
by  Ag. 

(3)  AgCl  Ppt.     Dissolve  the  mineral  in  cone.  HNOs  and  dilute 
the  sol. ;  add  a  few  drops  of  HC1  or  a  little  common  salt  and  a  white 
ppt.  of  AgCl  forms.     Darkens  on  exposure  to  light  and  is  sol.  in 
ammonia.     Collect  ppt.  on  filter  paper  and  test  according  to  (1) 
above. 

SODIUM  (Na;  univalent;  at.wt.  23) 

(1)  Flame  Color.  Deep  pure  yellow,  invisible  through  dark  blue 
glass.  For  non-vol.  silicates  mix  powdered  mineral  with  equal 
volume  of  powdered  gypsum  and  heat  on  the  point  of  a  Pt  wire  which 
has  been  previously  moistened  so  that  powder  will  adhere. 

Everything  -that  is  touched  by  the  hands  gives  a  distinct  Na 
flame,  so  delicate  is  the  test;  hence  it  is  of  diagnostic  value  only 
when  the  flame  color  is  deep  and  persistent. 

(2) « Alkaline  Reac.  Some  Na  minerals,  like  those  containing 
most  other  alkalis  and  the  alkaline  earths,  give  alkaline  reac.  on 
moist  turmeric  paper  after  ignition. 

For  Na  in  silicates,  see  Silicon  (2),  page  185. 

STRONTIUM  (Sr;  bivalent;  at.wt.  87.6) 

(1)  Flame  Color.  Crimson,  from  fragment  in  forceps  or  from 
powder  on  Pt  wire  moistened  with  HC1  (faint  yellow  through  green 


REACTIONS  FOR  THE  ELEMENTS  187 

glass).     Much  like  the  Li  flame;  redder  than  the  Ca  flame  and  more 
persistent. 

(2)  Alkaline  Reac.     Like  many  minerals  containing  alkalis  and 
other  alkaline  earths,  some  Sr  minerals  give  alkaline  reac.  on  moist 
turmeric  paper  after  ignition.     No  Li  minerals  give  this  reaction. 

(3)  Sulphate  ppt.     A  sol.  of  a  Sr  mineral  gives  a  white  ppt.  of 
SrSO4  on  addition  of  a  few  drops  of  dil.  H^SC^  (dif.  from  Li)  if  sol. 
is  not  very  dilute  or  too  much  acid.     Ppt.  does  not  dissolve  on  addi- 
tion of  water  and  boiling,  as  does  CaSO4.     This  test  is  useful  for 
silicates  and  phosphates,  which  do  not  yield  tests  (1)  and  (2). 

SULPHUR  (S;  bivalent  and  sexivalent;  at.wt.  32.1) 

Sulphides : 

(1)  Fumes  in  o.t.  and  on  ch.    Finely  powdered  sulphides  in  o.t. 
give  sharp  pungent  S02  fumes,  which  give  acid  reac.  on  moist  litmus 
paper  in  upper  end  of  tube.     With  Fe  and  Cu  some  white  fumes  of 
SOs  appear  and  H2SO4  condenses  in  the  tube.     Similar  results  on 
ch.  in  o.f.,  but  less  delicate.     Some  sulphides  give  blue  flame  from 
burning  S  on  ch. 

(2)  Subl.  in  c.t.     Some  sulphides  yield  in  c.t.  a  subl.  of  S,  which 
is  a  reddish  liquid  while  hot  and  a  yellow  solid  when  cold. 

(3)  Reac.  with  Soda.    Fuse  powdered  mineral  b.b.  on  Pt  foil, 
ch.,  or  a  flake  of  mica,  with  3  volumes  of  soda,  place  the  mass  on 
clean  Ag  and  moisten  with  water;  a  black  stain  of  Ag2S  forms.     The 
fused  mass  moistened  with  HC1  yields  H2S,  as  in  (5)  below.     This 
test  is  not  reliable  in  the  presence  of  Se  and  Te.     Also  the  gas  or  ch. 
may  give  a  slight  reac.  for  S. 

(4)  Sol.  in  HNOs.     In  hot  cone.  HNOs  sulphides  are  oxidized 
with  the  formation  of  H2SO4  and  red  NO2  fumes.     Dilute  part  of 
the  sol.  and  add  BaCl2;  a  white  ppt.  of  BaS04  forms.     Free  S  may 
also  float  on  the  solution,  either  yellow  or  blackened  with  particles 
of  the  mineral. 

(5)  H2S  with  HC1.     Some  sulphides  dissolve  in  HC1  with  the 
evolution  of  H2S  gas,  which  is  'recognized  by  its  offensive  odor. 

Sulphates : 

(1)  BaSO4  ppt.    BaCl2  added  to  a  dil.  HC1  sol.  of  a  sulphate 
gives  a  white  ppt.  of  BaSO4,  which  does  not  dissolve  on  addition  of 
water  and  boiling,  as  does  CaSO4. 

(2)  Reac.  with  Soda.     Fuse  the  powdered  mineral  with  equal 
volume  of  powdered  ch.  aj.:d  2  volumes  of  soda  on  ch.,  Pt  foil,  or  a 


188  DETERMINATION  BY  BLOWPIPE  TESTS 

flake  of  mica  till  effervescence  ceases;  then  test  on  Ag  or  with  HC1 
as  in  (3)  for  sulphides. 

TELLURIUM  (Te;  bivalent;  at.wt.  127.5) 

(1)  Color  of  Sol.     Finely  powdered  mineral  heated  gently  in 
cone.  H2S04  gives  reddish  violet  sol.     After  cooling  add  H20;  color 
disappears  and  grayish  black  ppt.  of  Te  forms.     Similar  color  from 
Mn  minerals  with  cone.  H^SO*  does  not  disappear  on  dilution. 

(2)  Subl.  on  ch.     Heated  in  o.f.  on  ch.  a  white  subl.  of  TeCb 
forms  near  assay,  resembling  Sb2Os.     Subl.  is  vol.  in  r.f.  and  gives  a 
pale  greenish  color  to  the  flame.     Similar  results  in  o.t. 

(3)  Subl.  in  c.t.    Metallic  globules  of  Te  and  white  subl. 

TIN  (Sn;  tetravalent;  at.wt.  119) 

(1)  Reduction  by  H.    With  dil.  HC1  and  fragments  of  Zn  cas- 
siterite  develops  a  dull  gray  coating  of  metallic  Sn,  which  becomes 
bright  and  gives  the  characteristic  odor  of  Sn  on  flesh  when  rubbed 
between  the  fingers. 

(2)  Metal  and  Subl.  on  ch.     The  powdered  mineral  fused  on  ch. 
in  r.f.  with  equal  volume  of  powdered  ch.  and  2  volumes  of  soda  gives 
globules  of  white  malleable  Sn,  which  are  bright  in  r.f.  and  become 
dull  in  the  air.     Long-continued  ignition  gives  a  white  subl.  of  SnC>2 
on  ch.     In  somewhat  cone,  warm  HNO3  the  metal  does  not  dissolve 
but  forms  white  H^SnOs.     Distinguished  from  Pb  and  Bi  by  accom- 
panying subl.  on  ch.  and  from  Ag  by  subl.  and  dull  surface  of  globule 
in  air. 

For  a  delicate  borax  bead  test,  see  Copper  (3),  page  179. 

TITANIUM  (Ti;  trivalent  and  tetravalent;  at.wfc.  48.1) 

(1)  Color  of  Sol.     After  fusion  with  borax  or  soda  and  solution 
in  HC1,  the  sol.  assumes  a  delicate  violet  color  on  boiling  with  Sn. 

(2)  S.ph.  Bead  Reac.     In  o.f.  yellow  while  hot,  colorless  cold;  in 
r.f.  yellow  hot,  delicate  violet  cold.     Best  reduced  with  a  granule  of 
Sn  on  ch.     When  other  coloring  elements  are  present  use  test  (1), 
above. 

(3)  Test  with  H2O2.    Fuse  the  mineral  with  soda,  boil  in  a  small 
amount  of  cone.  H2SO4  and  an  equal  volume  of  water  till  clear. 
Dilute  and  add  H2O2J   the  sol.  becomes  yellow  to  amber,  according 
to  the  quantity  of  Ti. 


REACTIONS   FOR  THE  ELEMENTS  189 

TUNGSTEN  (W;  sexivalent;  at.wt.  184) 

(1)  S.ph.  Bead  Reac.    In  o.f.  colorless;   in  r.f.  green  hot,  fine 
blue  cold. 

(2)  Residue  in  HC1.    When  decomposed  by  HC1  a  yellow  residue 
of  WOs  is  obtained.     Add  Sn  and  continue  boiling;   a  blue  color  is 
produced,  which  finally  changes  to  brown.     If  insol.  in  HC1,  fuse 
powder  on  Ft  wire  with  6  volumes  of  soda,  pulverize  and  dissolve  in 
water,  filter,  acidify  with  HC1,  and  boil  with  Sn.     The  sol.  becomes 
blue. 

(3)  Reduction  on  Al.    To  a  drop  of  water  on  Al  add  the  finely 
powdered  mineral  and  a  small  drop  of  HC1.     A  blue  color  develops 
on  standing. 

URANIUM  (U;  tetravalent  and  sexivalent;  at.wt.  238.5) 

(1)  S.ph.  Bead  Reac.    In  o.f.  yellow  while  hot,  yelh.-green  cold; 
in  r.f.  a  fine  green. 

VANADIUM  (V;  pentavalent;  at.wt.  51) 

(1)  S.ph.  Bead  Reac.     In  o.f.  yellow  to  deep  amber,  fading  a 
little  on  cooling;  in  r.f.  dirty  greenish  while  hot,  fine  green  cold. 

(2)  Color  of  Sol.     To  an  acid  sol.  add  a  few  drops  of  H2O2.     The 
sol.  becomes  reddish-brown  from  pervanadic  acid,  HVO^.     A  very 
delicate  test. 

ZINC  (Zn;  bivalent;  at.wt.  65.4) 

(1)  Subl.  on  Ch.  Make  a  paste  of  the  finely  powdered  mineral, 
half  its  volume  of  soda,  and  a  little  water.  The  mineral  must  first 
be  thoroughly  roasted  if  S,  As,  or  Sb  is 
present.  Heat  some  of  the  paste  in  a 
small  loop  of  Pt  wire,  which  is  held 
about  half  an  inch  from  the  surface  of 
charcoal  (Fig.  81),  so  that  volatilized 
products  are  carried  by  the  flame  di- 
rectly against  the  coal.  Using  a  small 
bead  and  an  intensely  hot  reducing  flame, 
Zn  is  reduced  to  the  metallic  state,  vola- 
tilized, and  then,  uniting  with  O  at  the 

i.  -j       e  ^     n  •     j         s*  j  FIG.  81.— Method  for  Zinc 

outside  of  the  flame,  is  deposited  as  a  Sublimate 

circular  coating,  which  is  canary-yellow 

while  hot  and  white  when  cold.     If  a  spot  has  previously  been 


190  DETERMINATION   BY  BLOWPIPE   TESTS 

moistened  with  Co(NOs)2  sol.,  the  sublimate  is  grass-green  at  that 
point. 

(2)  Flame  Color.     A  large  fragment  heated  near  the  tip  of  the 
blue  flame  colors  it  in  streaks  a  vivid  pale  bluish-green. 

(3)  Change  of  Color.    Many  Zn  minerals  are  straw-yellow  or 
canary-yellow  while  hot  and  white  when  cold. 

ZIRCONIUM  (Zr;  tetravalent;  at.wt.  90.6) 

(1)  Turmeric  Paper  Test.  Fuse  the  powdered  mineral  with 
soda  in  a  loop  of  Pt  wire  and  dissolve  the  bead  in  a  small  amount  of 
HC1.  Turmeric  paper  placed  in  the  solution  assumes  an  orange 
color,  which  is  detected  by  comparing  with  a  piece  of  turmeric  paper 
in  another  tube  containing  only  acid. 


TABLES    FOR    THE   DETERMINATION  OF 

MINERALS  BY  MEANS  OF  THE  BLOWPIPE 

AND  CHEMICAL  TESTS 


PRELIMINARY  INSTRUCTIONS  AND  PRECAUTIONS 

THE  tables  are  constructed  on  the  plan  of  eliminating  one  group 
of  minerals  after  another  until  the  proper  species  is  found;  hence 
the  order  as  given  must  be  followed  strictly,  both  in  the  general 
table  and  in  the  sections  to  which  it  refers. 

Each  test  should  be  recorded  as  soon  as  made,  whether  results 
are  negative  or  positive.  This  may  be  done  in  systematic  order  in 
a  notebook,  as  suggested  on  the  next  page. 

If  the  crystal  system  can  be  determined,  either  from  crystals  or 
from  cleavage,  comparison  with  the  crystal  tables,  pages  266  to  274, 
will  often  prove  the  most  convenient  means  of  identification. 

Whenever  possible,  tests  should  be  made  only  upon  fresh, 
homogeneous  material,  preferably  crystalline.  If  an  impurity  can 
be  detected  its  effect  must  be  carefully  allowed  for  and  not  attrib- 
uted to  the  mineral.  For  example,  surface  stains  of  iron  oxide 
and  thin  films  or  small  amounts  of  intermingled  calcite  or  other 
carbonate  are  often  present  and  may  mislead  by  discoloring  the  acid 
or  yielding  a  temporary  effervescence.  In  case  of  doubt,  decant 
after  boiling  and  note  whether  or  not  the  same  results  are  obtained 
with  fresh  acid. 

The  powdered  mineral  required  for  many  of  the  tests  should  be 
prepared  by  crushing  and  grinding  (not  pounding)  small  grains  of 
pure  material  under  a  hammer  on  any  clean  surface  of  iron  or  steel. 
(Fig.  69.)  If  the  mineral  is  rare  and  but  little  can  be  had  for  deter- 
mination, fragments  may  be  wrapped  in  two  or  three  folds  of  paper 
and  pounded  with  a  hammer. 

All  tests  must  be  made  with  care,  and  only  clear,  decided  reactions 
taken  into  account.  Weak  uncertain  results  may  be  due  to  the 

191 


192     TABLES  FOR  THE  DETERMINATION  OF  BLOWPIPE  TESTS 

presence  of  a  small  amount  of  some  impurity,  but  often  they  are 
the  results  of  careless  or  hasty  manipulation.  In  every  test  follow 
closely  the  detailed  instructions,  pages  156  to  174. 

The  importance  of  scrupulous  care  in  making  acid  tests  and 
critical  observation  of  the  results  cannot  be  over-emphasized.  The 
student  should  be  thoroughly  familiar  with  the  instructions  on  pages 
170  to  173. 

Dilute  HC1  (that  is,  cone.  HC1  with  an  equal  volume  of  water) 
is  always  understood  in  acid  tests,  unless  otherwise  specified.  In 
many  tests  the  concentrated  acid  will  not  yield  as  good  results. 

Do  not  fill  a  test  tube  with  acid  or  other  reagent  to  a  depth 
much  greater  than  its  diameter,  if  it  is  to  be  boiled. 

When  igniting  a  mineral  alone  on  charcoal,  use  small  particles — 
about  the  size  of  a  pin  head — and  use  only  as  many  as  can  be  thor- 
oughly heated  in  the  blowpipe  flame. 

Do  not  use  the  Pt-tipped  forceps  with  a  mineral  of  metallic  luster 
nor  with  one  that  yields  a  rnetal  on  charcoal. 

Many  of  the  "Instructions  and  Precautions"  given  in  connection 
with  the  physical  tables,  page  12,  also  apply  equally  here. 


LABORATORY  RECORDS 

For  each  mineral  determined  record  should  be  made  of  tests  and 
diagnostic  characters,  in  the  order  in  which  they  are  met  in  the  tables. 
Small  loose-leaf  note-books,  with  paper  about  3^  by  5|  inches, 
furnish  ample  space  and  have  been  found  most  convenient  for  this 
purpose. 

Such  records  are  particularly  useful  in  case  of  error,  and  the 
separation  into  two  parts,  belonging  to  the  general  and  the  special 
tables,  respectively,  is  also  an  advantage.  The  condensed  skeleton 
form  saves  much  of  the  student's  and  instructor's  time  without 
sacrificing  clearness. 

Emphasis  should  be  placed  on  the  necessity  of  recording  each 
test  immediately  upon  its  completion. 

The  following  records  of  the  determination  of  pyrite  and  ortho- 
clase  will  serve  as  illustrations. 


LABORATORY  RECORDS 


193 


No.  37 

Luster  metallic 
Fus.  3;  SO2  fumes 
No  As  nor  Sb 


(Sec.  3,  p. 

No  Ag,  Pb,  nor  Cu 
Becomes  mag.  in  o.  f. 
Color  brass-yellow 
Soluble  in  cold  cone.  HNOs 
No  S  residue 

P  YRITE,  FeS2 
Use:  Mfr.  H2S04 

J.  R.  Brown 
May  20,  1921 


No.  38 

Luster  vitreous;  cl.  pearly 
Fus.  4~5;  no  flame  color 
No  metal  w.  ch.  and  soda 
Not  mag.  nor  alk.  after  ign. 
Insoluble  in  HC1 
Cl  2  direc.  about  90° 

(Sec.  23,  p.  238} 

G.  2.57;  Feldspar  Group 
K  flame  w.  gypsum 
Cl.  faces  not  striated 

ORTHOCLASE  KAlSi308 
Use:  Pottery  mfr. 


J.  R.  Brown 


May  20,  1921 


GENERAL  TABLE 


(For  abbreviations,  see  page  285) 

NOTE. — Constant  reference  should  be  made  to  the  instructions  for  carrying 
out  the  various  chemical  and  blowpipe  tests  until  the  methods  of  procedure  have 
become  familiar.  For  this  purpose  the  tests  have  been  grouped  under  the  respect- 
ive elements,  alphabetically  arranged,  on  the  pages  immediately  preceding  these 
tables. 

I.  METALLIC  OR  SUBMETALLIC  LUSTEK 

A.  Fusible,  at  least  on  thin  edges  (fus.  1-5),  or  volatile:  BEG.   PAGE 

1.  As  minerals.     White  subl.  on  ch.  far  from  assay;    commonly 

also  garlic  odor 1       196 

2.  Sb  minerals. — Dense  white  subl.  on  ch.  near  assay 2       198 

3.  Sulphides,  no  As  nor  Sb. — SC>2  fumes  in  o.t.,  if  not  on  ch.;  acid 

reaction  with  moist  litmus  paper  placed  in  upper  end  of  tube .       3       200 

4.  Not  previously  included 4      202 

B.  Infusible  or  nearly  so  (fus.  above  5) : 

1.  Fe  minerals. — Strongly  magnetic  or  become  so  after  heating 

in  r.f.  and  cooling 5      206 

2.  Mn  minerals. — Minute  quantity  gives  Mn  reaction  in  soda  or 

borax  bead;  sol.  in  HC1  with  evolution  of  Cl  gas 6      208 

3.  Not  previously  included 7      210 

II.  LUSTER  NOT  METALLIC 

A.  Easily  volatile  or  combustible 8      212 

B.  Fusible,  at  least  on  thin  edges  (fus.  1-5),  or  slowly  or  partially 

volatile: 

Part  I.  Metal  globules  when  fused  on  ch.  with  equal  volume  of 
powdered  ch.  and  3  volumes  of  soda : 

1.  Pb  minerals. — Yellow  subl.  and  Pb  globules  on  ch.;    with 

von  Kobell's  flux  a  chrome-yellow  coat,  darker  while  hot.       9      214 

2.  Cu  minerals. — Cu  globules;  Cu  reactions  with  acids 10      214 

3.  Ag  and  Bi  minerals. — Ag-white  metallic  globules 11       216 

Part  II.  Magnetic  after  heating  in  r.f.  and  cooling;    Fe,  Ni,  and 

Co  minerals: 
1.  Fine  powder  sol.  in  HC1  without  residue  or  formation  of  gel. 

silica  upon  evaporation 12      218 

194 


GENERAL  TABLE  195 

2.  Fine  powder  sol.  in  HC1  with  gel.  silica,  or  decomposed  with    8EC.    PAGB 

separation  of  silica  (latter  more  translucent  and  settles 

more  slowly  than  mineral  powder) 13       220 

3.  Fine  powder  insol.  in  HC1  or  nearly  so 14      220 

Part  III.  Not  included  in  the  foregoing  Parts  I  and  II. 

1.  Alkaline  reaction  on  moist  turmeric  paper  after  intense 

ignition: 

a.  Fine  powder  easily  and  completely  soluble  in  water.  .  .      15      224 

b.  Fine  powder  insol.  in  water  or  only  slowly  or  partially 

soluble 16      226 

2.  Fine  powder  sol.  in  HC1  without  residue  or  formation  of  gel. 

silica  upon  evaporation 17      228 

3.  Fine  powder  sol.  in  HC1  with  gel.  silica: 

a.  Give  water  in  closed  tube 18      230 

b.  Little  or  no  water  given  in  closed  tube 19       230 

4.  Fine  powder  decomposed  by  HC1  with  separation  of  flaky 

or  granular  silica   (more  translucent  and  settles  more 
slowly  than  mineral  powder)   or  yellow  WOs    powder: 

a.  Give  water  in  closed  tube 20      232 

b.  Little  or  no  water  given  in  closed  tube 21       234 

5.  Fine  powder  insoluble  in  HC1  or  nearly  so : 

a.  Micaceous,  scaly,  or  foliated 22  236 

&.  Distinct   cleavage  2   directions — feldspars,   amphiboles, 

pyroxenes 23  238 

c.  Mn  reaction  in  soda  bead 24  240 

d.  Not  previously  included 25  242 

C.  Infusible  or  nearly  so  (fus.  above  5) : 

1.  Alkaline  reaction  on  moist  turmeric  paper  after  intense  ignition.     26       246 

2.  Fine  powder  sol.  in  HC1  without  residue  or  formation  of  gel. ' 

silica  upon  evaporation 27      248 

3.  Fine  powder  sol.  in  HC1  with  gel.  silica 28      252 

4.  Fine  powder  decomposed  by  HC1  with  separation  of  flaky  or 

granular  silica  (more  translucent  and  settles  more  slowly  than 

mineral  powder)  or  yellow  WO3  powder 29      254 

5.  Fine  powder  insol.  in  HC1  or  nearly  so: 

a.  Can  be  scratched  with  knife  blade  (H  below  6) 30      254 

b.  Cannot  be  scratched  with  knife  (H  6  or  harder) 31      258 


196 


SECTION  1.     Metallic  luster; 


Name. 

Composition. 

Vol.  on  ch.  without  fusion 

As  subl.  in  c.t. 

ARSENIC 
(See  p.  28) 

As 

(Sb  Iso.  w.  As) 

Mag.  globule  on  ch. 

(Compare  Co  and   Ni  min- 
erals below.) 

As  and  S  reac.  in  o.t. 
As  in  c.t.  ;    red  subl. 
precedes 

ARSENOPYRITE 

(Mlsplckel) 
(See  p.  16) 

FeAsS 
(Co  Iso.  w.  Fe) 

As,  but  little  or  no  S 

Lollingite 
(Leucopyrlte) 
(See  p.  15) 

FeAs2  to  Fe3As4 
(Some  S,  somet.  Co.) 

Cu  flame  on  ch.  after  roast- 
ing  and    moistening   with 
HC1.     SO2  fumes  in  o.t. 
Pearceite    has    triangular 
markings  on  basal  planes. 

Disting.  by  phys.  prop- 
erties 
(Cp.  tetrahedrite) 

ENAKGITE 
(See  p.  20) 

Cu3AsS4 
(Some  Sb) 

Tennantite 
[See  p.  21) 

Cu3AsS3 
(Ag,  Zn,  Fe,  Sb,  Iso.) 

Ag  w.  soda  on  ch. 
(Cp.  polybasite) 

PEARCEITE 
(See  p.  20) 

(Ag,Cu)9AsS6 

Cu  flame  on  ch.  as  above;  no 
SO2  fumes  in  o.t. 

Disting.  by  phys.  prop- 
erties.      All    tar.     to 
bnh.  color.     Whitney- 
ite  is  rdh.  on  rubbed 
surface  and  malleable 

Domeykile 

Cu3As 

Algodonite 

Cu6As 

Whitneyite 

Cu9As 

Rose  col.  sol.  in  cone.  HNO3; 
Co  in  borax  bd.  after  roast- 
ing 
(Compare     Ni     minerals, 
below) 

As  subl.  in  c.t. 

SMALTITE 
(See  p.  16) 

CoAs2 
(Fe,  NI  Iso.  w.  Co) 

As  and  S  reac.  in  o.t., 
little  or  none  in  c.t. 

COBALTITE 

(See  p.  15) 

CoAsS 
(Fe  Iso.  w.  Co) 

Glaucodot 

(Co.Fe)AsS 

Apple-grn.  sol.  in  HNOa  and 
dime  thy  Iglyoxime  test  for 
Ni,  abundant  ppt.;    Ni  in 
borax    bd.    after   roasting. 
(May  be  masked  by  Co) 

As  subl.  in  c.t. 

CHLOANTHITE 
(See  p.  16) 

NiAs2 
(Fe,  Co  Iso.  w.  NI) 

As  in  c.t.  on  intense  ign. 

NlCCOLITE 
(Copper  Nickel) 
(See  p.  25) 

NiAs 
(Fe,  Co  Iso.  w.  NI)' 

As  and  S  reac.  in  o.t. 
S  res.  in  cone  HNOs 

GERSDOHFFITE 
(See  p.  15) 

NiAsS 
(Fe.  Co  Iso.  w.  NI) 

Ag  in  HNO3  sol.,  S  set  free 

Abund.  deep  red   subl. 
in  c.t.,  rdh.-yel.  cold; 
slight  S  subl.  above  it 

PROUSTITE 
(Ruby  Silver) 
(See  p.  137) 

AgsAsSs 
(Somet.  Sb) 

fus.  1-5  or  vol.;  As  subl.  on  ch. 


197 


Color. 

Streak. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Sn-wh.;  tar. 
dk.  gry. 

Gry- 

3* 

5.6-5.7 

Vol. 

Hex.  rhom.; 
us.  crusts 

C.  1,  basal,  per. 
F.  uneven 

Ag-wh.  to 
Fe-gry. 

Blk. 

5£-6 

5.9-6.2 

2 

Orth.;  gran.; 
com  p. 

C.  2,  prism., 
68°,  poor 
F.  uneven 

Ag-wh.  to 
steel-gry. 

Blk. 

51-6 

7.0-7.4 

2 

Orth.;  gran.; 
comp. 

C.  1,  basal,  poor 
F.  uneven 

Gryh-blk. 

Gryh-blk. 

3 

4.4-4.5 

1 

Orth.;  gran.; 
comp. 

C.  2,  prism.,  per., 
82° 
F.  uneven 

Dk.  Pb-gry. 
to  Fe-blk. 

Blk.  to  dk. 
cherry-red 

3  -4 

4.4-5.1 

a 

Iso.  tetrh.;  xls. 
Figs.    13,    14, 
17;  comp. 

F.  uneven 

Blk. 

Blk. 

3 

6.1-6.2 

1 

Mon;  tabular, 
comp. 

F.  conch. 

Sn-wh.  to 
steel-gry. 

Gry. 

3  -3| 

7.2-7.7 

2 

Massive 

F.  uneven 

Steel-gry. 

Gry. 

4 

7.6 

2 

Massive 

F.  uneven 

Pale  rdh. 
to  gryh-wh. 

Ag-wh. 

3* 

8.4-8.6 

2 

Massive 

Malleable 
F.  hackly 

Sn-wh. 

Blk. 

5  £-6 

6.4-6.6 

21 

Iso.   pyrito.  ; 
gran.  ;  comp. 

C.  4,  oct.  70§°, 
poor 
F.  uneven 

Ag-wh.   to  gry. 
w.  rdh.  tone 

Blk. 

5* 

6.0-6.3 

2-3 

Iso.  pyrito.; 
Figs.  5,  18,  20 

C.  3,  cubic,  poor 
F.  uneven 

Gryh-wh. 

Blk. 

5 

5.9-6.0 

2-3 

Orth. 

C.  basal 
F.  uneven 

Sn-wh. 

Gryh-blk. 

5  £-6 

6.4-6.6 

2 

Iso.  pyrito.  ; 
gran.;  comp. 

C.  4,  oct.,  70|° 
F.  uneven 

Pale  Cu-red 

Brnh-blk. 

5  -5J 

7.3-7.7 

2 

Hex.;  comp.; 
dissem. 

F.  uneven 

Sn-wh. 

Blk. 

51 

5.6-6.2 

2 

Iso.  pyrito.; 
gran. 

C.  3,  cubic,  poor 
F.  uneven 

Scarlet  to  ruby- 
red 

Scarlet 

2  -2£ 

5.5-5.6 

1 

Hex.  rhom., 
hemimor; 
compact. 

C.  3,  rhom.  poor 
F.  conch. 

198 


SECTION  2.     Metallic  luster; 


Name. 

Composition. 

Easily  and  completely  vol. 
on  ch.  ;  no  Pb  reac.  Stib- 
nite,  slender  xls.  slightly 
flexible 

Wh.  slowly  vol.  subl. 
in  o.t. 

Antimony 
(See  p.  28) 

Sb 
(Somet.  Ag,  Fe,  As) 

SC>2  and  wh.  non-vol. 
subl.  in  o.t. 

STIBNITE 
(Antimony  Glance) 
(See  p.  18) 

Sb2S3 

Cu  reac.  in  HNO3  sol.  No 
Pb  or  Ag  globule  w.  soda 
on  ch. 

May  contain  Pb,  Ag, 
Zn,  Fe,  and  As 

TETRAHEDRITE 

(Gray  Copper) 
(See  p.  21) 

Cu3SbS3 

(Fe,  Zn,  Pb,  Ag  Iso.  w. 
Cu;  As  Iso.  w.  Sb) 

Ag  reac.  in  HNO3  sol.  w. 
HC1;  no  Pb.  Ag  globule 
after  roasting  and  fus.  w. 
soda  on  ch.  Subl.  red  to 
lilac  when  only  Ag,  Sb, 
and  S  are  present 

Cu  reac.  in  HN03  sol.; 
mineral  gray 

FBEIBERGITE 
(Ag  Tetrahedrlte) 
(See  p.  21)  . 

(Cu,Ag)8Sb2S7 
(Fe,  Zn  Iso.  w.  Cu2;  some 
As) 

Deep  red  to  blk.;  st. 
Indian-red 

PYRARGYRITE 
Ruby  Silver,  Dark  Red 
Silver  Ore) 
(See  p.  129) 

Ag,SbS8 
(Somet.  As) 

Blk.,  stout  6-sided 
(orth.)  prisms 

STEPHANITE 
(Brittle  Silver  Ore) 
(See  p.  18) 

Ag5SbS4 

Blk.,  6-sided  (mon.) 
plates;  triangular 
markings  on  basal 
plane 

POLYBASITE 

(Cp.  peareclte,  p.  196) 
(See  p.  19) 

(Ag,Cu)9SbS6 
(As  Iso.  w.  Sb) 

Sb  and  Ag  reac.  No  S. 
Sectile 

Dyscrasite 
(See  p.  28) 

Ag3Sb  to  AgeSb 

Pb  reac.  after  roasting  and 
fus.  on  ch.  w.  von  Kobell's 
flux 

Cu  reac.  with  HNO3 
sol.;  steel-gry. 

BOURNONITE 
(Cogwheel  Ore) 
(See  p.  20) 

PbCuSbS3 

No  Ag  or  Cu 

JAMESONITE 
(Feather  Ore) 
(See  p.  14) 

Pb2Sb2S5 
(Often  Fe) 

Zinkenite 

PbSb2S4 

f us.  1-5  or  vol. ;  Sb  subl.  on  ch. 


199 


Color. 

Streak. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Sn-wh. 

Sn-wh. 

3  -3| 

6.6-6.7 

1 

Hex.  rhom.; 
us.  mass. 

C.  1,  basal,  per. 
F.  uneven 

Pb-gry. 

Pb-gry. 

2 

4.5-4.6 

1 

Orth.;  long 
prism.;  xls. 

C.  1,  pinac.  per. 
F.  uneven 

Gry.  to 

Fe-blk. 

Gry.  to 
Fe-blk. 

3  -A 

4.4-5.1 

U 

Iso.  tetrh., 
Figs.  13,  14, 
17;  comp. 

F.  uneven 

Steel-gry. 

Blk.,     often 
rdh. 

3  -4 

4.8-5.0 

11 

Iso.  tetrh. 

F.  uneven 

Deep  red  to 
blk. 

Purplish 
red 

2|-3 

5.8-5.9 

1 

Hex.  rhom.; 
hemimor.; 
dissem.; 
comp. 

C.  3,  rhom., 

poor,  72° 
F.  conch., 
uneven 

Fe-blk. 

Fe-blk. 

2  -2| 

6.2-6.3 

1 

Orth.;  comp., 
dissem. 

F.  uneven 

Fe-blk. 

Blk. 

2  -3 

6.0-6.2 

1 

Mon.,  tabular; 
comp.  ; 
dissem. 

C.  1,  basal,  poor 
F.  uneven 

Ag-wh. 

Ag-wh. 

3* 

9.4-9.9 

H 

Orth.;   comp.; 
gran. 

C.  3,  basal  and 
prism,  56°, 
68°  124° 

Steel-gry. 

Fe-gry. 

2f-3 

5.7-5.9 

1 

Orth.;  gran.; 
cogwheel 
twins 

F.  uneven 

Blkh-gry. 

Gryh-blk. 

2  -3 

5.5-6.0 

1 

Orth.;  acic., 
feathery 

C.  1,  basal,  per. 
F.  uneven 

Steel-gry. 

Steel-gry. 

3  -3* 

5.3-5.4 

i 

Orth. 

F.  uneven 

200 


SECTION  3.     Metallic  luster; 


Name. 

Composition. 

Ag  globule  in  o.f. 
on  ch. 

Contains  only  Ag  and  S. 
Sectile 

ARGENTITB 

(Silver  Glance) 
(See  p.  18) 

Ag2S 

Pb  globule  and  yel. 
subl.  on  ch. 

NoBi 

GALENA 
(  Galenlte) 
(See  p.  19) 

PbS 
(Often  some  Ag) 

Cu  flame  on  ch.  af- 
ter roasting  and 
moistening  w. 
HC1 

Mag.     in     o.f. 
(Stannite  on- 
ly after  long 
ign.) 
(Millerite,    be- 
low,         may 
have  Cu  im- 
purities) 

Brass-yel. 

CHALCOPYRITE 
(Copper  Pyrites) 
(See  p.  24) 

CuFeS2 

Brnh-bronze, 
purple  tar. 

BORNITE 

(Peacock,  Ore) 
(See  p.  24) 

Cu6FeS4 

Steel-gray.;  wh. 
subl.  in  o.f. 

Stannite 
(Tin  Pyrites) 
(See  p.  15) 

Cu2FeSnS4 
(Zn  Iso.  w.  Fe) 

Not  mag.  in  o.f. 
(unless       im- 
pure from  ad- 
mixture       of 
bornite,  etc.) 

Cu  in  r.f.  after 
roasl  ing.  Co- 
vellite  much 
Sinc.t.,Chal- 
cocite  none 

CHALCOCITE 

(Copper  Glance) 
(See  p.  19) 

Cu2S 
(Somet.  Fe) 

COVELLITB 
(Indigo  Copper) 
(See  p.  17) 

CuS 

Ag  reac.  in 
HNO3  sol. 

STHOMEYERITE 
(See  p.  20) 

AgCuS 

Mag.  in  o.f.;  no  Cu. 
Contains  Fe,  Co, 
orNi, 

(Continued  on  next 
page) 

Pale  brass-yel.     Completely  sol. 
in  cold  cone.  HNO3 

PYRITE 
(Iron  Pyrites:  Fool'8 
Gold) 
(See  p.  26) 

FeS2 
(Somet.  Cu.  Au.  Nl,  Co) 

Pale  brass-yel  to  wh. 
S  separates  from  cold  cone. 
HNO3  sol. 

MARCASITE 
(White  Iron  Pyrites) 
(See  p.  26) 

FeS2 
(Somet.  As) 

Brnh-bronse;  us.  mag.;  st.  blk. 

PYRRHOTITE 

(Magnetic  Pyrites; 
Mundlc) 
(See  p.  25) 

FeS 
(Nl  Iso.  w.  Fe) 
S  in  sol.  up  to  3j% 

Zn   reac.   w.    soda;     submetallic 
luster 

SPHALERITE 
(Zinc  Blende;  Black  Jack) 
(See  p.  88) 

ZnS 
(Fe,  Mn.  Cd.  Iso.  w.  Zn) 

Wurtzite 
(See  p.  130) 

ZnS 
(Some  Fe) 

fus.  1-5  or  vol;  no  As  nor  Sb;  SO2  in  o.t. 


201 


Color. 

StreaK. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi.- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Blkh-gry. 

Blkh-gry. 

2  -2J 

7.2-7.4 

Li 

Iso.,  us.  comp. 

F.  hackly, 
sectile 

Pb-gry. 

Pb-gry. 

2* 

7.4-7.6 

2 

Iso.;  us.  xls.  or 
gran. 
Fig.  5 

C.  3,  cubic,  per.  90° 

Brass-yel. 

Grnh-blk. 

3M 

4.1-4.3 

2 

Tet.  sphenoidal; 
us.  comp. 

F.  uneven 

Brnh-red 
bronze 
Purplish  tar. 

Pale 
gryh-blk. 

3 

4.9-5.4 

2* 

Iso.  ;  us.  comp. 

F.  uneven 

Steel-gry.  to 
Fe-blk. 

Blkh. 

4 

4.3-4.5 

1  1 

Tetrag.,  us. 
comp. 

F.  uneven 

Dk.  Pb-gry 
Blkh.  or 
blue  tar. 

Dk.  Pb-gry. 

2M 

5.5-5.8 

2| 

Orth.  ;  us.  mass. 

F.  conch. 

Indigo-blue 

Pb-gry.  to 
blk. 

IJ-3 

4.6 

2}  ' 

Hex.;  us.  comp. 
or  crusts 

C.  1,  basal,  per., 
thin  flakes 
flexible 

Dk.  steel-gry. 

Dk.  steel- 
gry. 

2  J-3 

6.2-6.3 

u 

Orth.; 
us.  comp. 

F.  uneven 
slightly  sectile 

Pale  brass-yel. 

Grnh-blk.  to 
brnh-blk. 

6  -6| 

4.9-5.2 

2|-3 

Iso.  pyrito.; 
Figs.  1,5,  18, 
20;  dissem. 

F.  uneven. 

Pale  yel.  to 
almost  wh. 

Gryh.  or 
brnh-blk. 

6  -6* 

4.8-1.9 

2  £-3 

Orth.;  tabular; 
pyram.; 
cockscomb  xls. 

C.  2,  prism.,  75°, 
poor 
F.  uneven 

Yelh.  to  bnh. 
bronze 

Blk. 

3Mi 

4.5-4.6 

2J-3 

Hex.; 
us.  comp., 

gran. 

C.  1,  basal,  poor 
F.  uneven 

Dk.  brn.  to  blk. 

Lt.  to  dk. 
brn. 

BM 

3.9-4.1 

5 

Iso.  tetr.; 
us.  gran., 
comp. 

C.  6,  dodec.,per., 
60°,  90°,  120° 
F.  conch. 

Bnh-bik. 

Brn 

3  HI 

3.9-4.0 

5 

Hex.  hemimor., 
fibr. 

F.  uneven', 
splintery 

202 


SECTION  3.— Concluded.     Metallic  luster; 


Name. 

Composition. 

Mag.  ino.f.;  no  Cu. 
—  Concluded 

HNO.,  sol.  grn.  Ni  in  borax  bd. 
after  roasting.  Millerite  capil- 
lary xls.  or  velvety  crusts; 
Pentlandite  gives  Fe  ppt.  w. 
am.  from  HNO3  sol. 

MILLERITE 
(Hair  Pyrites) 
(See  p.  24) 

NiS 
(Slender  xls.  elastic) 

PENTLANDITE 
(See  p.  25) 

(Fe,Ni)S 

HNO3  sol.  rose  col.  Co  in  borax 
bd.  after  roasting 

LlNNAEITE 

(See  p.  15) 

(Co,Ni)3S4 
(Fe,  Cu  too.  w.  Co) 

Hg  subl.  in  c.t.  with 
dry  soda 

SO2  and  Hg  in  o.t.,  blk.  subl.  in 
c.t. 

CINNABAR 
(See  p.  137) 

HgS 
(Us.  w.  Fei  Oj.  clay, 
bitumen) 

Bi  reac.   w.        von 
Kobell's  flux 

Te  reac.  w.  H2SO4 

Tetradymite 

Bi2(Te,S)3 

Contains  only  Bi  and  S 
Fuses  with  spiriting 

Bismuthinite 
(Bismuth  Glance) 
(See  p.  14) 

Bi2S3 

Mn     in  borax     bd. 
after  roasting 

H,S  in  HC1 

ALABANDITE 
(See  p.  148) 

MnS 

Rdh-violet  sol.  when  gently   heated   in   cone.  H2SO4 
(See  p.  188) 

TELLURIDES 
See  page  206 

SECTION  4.     Metallic  luster; 


Native  metal,  malleable 

Cu  reac.  w.  HNO3  sol. 

COPPER 

(See  p.  138) 

Cu 
(Often  Ag,  BI,  Hg) 

Ag  reac.  w.  HNO3  sol. 
(Cp.  amalgam  below) 

SILVER 
(See  p.  27) 

Ag 

(Somet.  w.  Au,  Cu,  Hg) 

Insol.   in   NHO3 

GOLD 
(See  p.  139) 

Au 
(Us.  w.  some  Ag) 

Insol.  in  NHO3;     much 
Ag 

Electrum 
(See  p.  139) 

(Au.Ag) 

Native     metal,     brittle     or 
liquid 

Bright  red  subl.  on  ch. 
w.  von  Kobell's  flux 

BISMUTH 
(See  p.  27) 

Bi 

(Often  S  and  Te) 

Hg  subl.  in  c.t.;    amal- 
gam leaves  Ag  res. 

Mercury 
'  (Quicksilver) 
(See  p.  26) 

Hg 

(Somet.  Ag) 

Amalgam 
(See  p.  28) 

(Ag.Hg) 

fus.  1-5  or  vol.;  no  As  nor  Sb;  SO2  in  o.t. 


203 


Color. 

Streak. 

Hard- 
ness. 

Specific. 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Brass-yel. 

Grnh-blk. 

3  -3| 

5.3-5.7 

IJ-2 

Hex.  rhom.  ; 
us.  capil,  fibr., 
crusts 

C.  rhom. 
F.  uneven, 
splintery 

Lt.  bronze  yel. 

Blk. 

3*-4 

4.6-5.1 

li-2 

Iso.,  gran., 
comp. 

C.  4,  oct.,  70£°, 
109£° 
F.  uneven 

Pale  steel-gry.  : 
tar.  Cu-red 

Gryh-blk. 

BJ 

4.8-5.0 

2 

Iso.,  xls., 
Fig.  1 

C.  cubic,  90° 
poor 
F.  uneven 

Conchineal-red 
to  bnh. 

Scarlet 

2  -2| 

8.1-8.2 

ii 

Vol. 

Hex.  rhom.; 
gran.,  earthy 

C.  3,  prism,  per., 
60° 
F.  uneven 

Pale-steel  gry. 

Gry. 

1M 

7.2-7.6 

U 

Hex.  rhom.; 
us.  bladed. 

C.  basal  per., 
thin  flakes 
flexible 

Lt.  Pb-gry. 

Lt.  Pb-gry. 

2 

6.4-6.5 

1 

Orth.;  gran., 
fol.,  fibr. 

C.  1,  pinac.,  per., 
slightly  sectile 

Fe-blk. 
Brn.  tar. 

Olive-grn. 

3|-4 

3.9-4.0 

3 

Iso.  tetr.; 
comp. 

C.  3,  cubic,  per. 
90° 
F.  uneven 

fus.  1-5  or  vol. ;  no  As,  Sb,  nor  S 


Cu-red, 
Tar-blk. 

Cu-red, 
shiny 

2f4 

8.8-8.9 

3 

Iso.  ;  scales, 
plates 

F.  hackly 
Duct,  and  mall. 

Ag-wh.;  tar. 
gry.  to  blk. 

Ag-wh., 
shiny 

2  1-3 

10.0-12.0 

2 

Iso.;  scales, 
wire 

F.  hackly 
Duct,  and  mall. 

Au-yel. 

Au-yel., 

shiny 

2J-3 

15.6-19.3 

2§-3 

Iso.;  scales, 
grains 

F.  hackly 
Duct,  and  mall. 

Yelh-wh. 

Yelh-wh., 
shiny 

2|-3 

12.5-15.5 

2-2* 

Iso.  ;  flakes, 
grains 

F.  hackly 
Duct,  and  mall. 

Ag-wh.,  rdh. 
hue 

Ag-wh., 
shiny 

2  -2\ 

9.7-9.8 

1 

Hex.  rhom.; 
us.  gran. 

C.  1,  basal,  per., 
sectile, 
slightly  mall. 

Sn-wh. 

0 

13.61iq. 
14.  4  xls. 

Vol. 

Iso.,  oct.  xls  at 
-39°  C. 
Fig.  1 

C.  3,  cubic,  90° 

Ag-wh. 

Ag-wh., 
shiny 

3  -3* 

13.7-14.1 

Iso.,  plates, 
coatings 

F.  uneven, 
conch. 

204 


SECTION  4.— Continued.     Metallic  luster: 


Name. 

Composition. 

Mag.    or    be- 
comes so  in 
r.f.      Con- 
tains Fe 
(Cp.  the  dark 
micas    (be- 
low), which 
sometimes 
become 
magnetic 

Little  or  no 
H2O  in  c.t. 

Strongly  mag.  before 
heating 

MAGNETITE 
(Magnetic  Iron  Ore; 
Lodestone) 
(See  p.  22) 

FeFe204 
(Somet.  Mg,  Mn,  Tl) 

Nonmag.  or  but  slightly 
so  before  heating 

HEMATITE 
(Specular  Iron) 
(See  p.  134) 

Fe2O3 
(Somet.  Tl,  Mg) 

Martite 
(See  p.  134) 

Fe2O8 

Much  H2O  in 

c.t. 

Botryoidal,  stalactitic, 
amorphous 

LIMONITE 

(Brown  Hematite; 
Bog  Iron  Ore) 

(See  p.131) 

FeO-OH-nH2O 

Prismatic  xls.;  lepid&- 
crocite  scaly 

GOETHITE 
(Lepldocroclte) 
(See  p.  142) 

FeO  -OH 

Rdh-blk.;   st.  dark  rdh- 
brn.     Us.  decrep.  vio- 
lently in  c.t. 

TURGITE 
(Hydrohematlte) 
(See  p.  144) 

FeO-OH,  Fe2O3,  H2O 

Cu  globule  in  r.f.  on  ch. 

Cuprite  submetallic  lus- 
ter; Melaconite  earth  y 
or  in  scales  (tenorite) 

CUPRITE 
(See  p.  141). 

Cu2O 

Melaconite 
(Tenorite) 
(See  p.  21) 

CuO 

Micaceous  or  foliated 

Decomposed  by  boiling 
cone.  H2SO4  (see  p. 
236) 

BIOTITE 
(Black  Mica) 
(See  p.  58) 

(K,H)2(Mg,Fe)2 
Al2(Si04)3 
(A  little  F,  often  Tl) 

PHLOGOPITE 

(Amber  Mica) 
(See  p.  106) 

H2KMg3Al(SiO4)3 
(A  little  F  and  Fe) 

W.  reac.  after  fus.  w.  soda 
Mag.  w.  little  soda 

Mn  in  soda  bd. 
(Cp.  hubnerite,  p.  234) 

WOLFRAMITE 
(See  p.  21) 

(Fe,Mn)WO4 

Little  or  no  Mn  reac. 

FERBERITE 
(See  p.  21) 

FeWO4 

(Some  Mn) 

Cb.  reac.  after  fus.  w.  borax 

Mn  in  soda  bd.  Mag. 
w.  little  soda 

COLUMBITE 

(See  p.  134) 

(Fe,Mn)Cb2O6 

Mn  in  soda  bd.  ;  U  in  s. 
ph.  bd. 

Samarskite 
(See  p.  133) 

(Fe,Ca,UO2)3 

(Ce,Y,Er)2 
(Cb,Ta)6O2i 

fus.  1-5  or  vol.;  no  As,  Sb,  nor  S 


205 


Color. 

Streak. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

.  Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Fe-black 

Blk. 

54-64 

4.9-5.2 

5  -5| 

Iso.;  oct.  and 
dodec.  Figs.  1, 
7,  8;  gran. 

P.  4,  oct.,  704°, 
1094° 
F.  conch., 
uneven 

Steel-gry.  to 
Fe-blk. 

Dk.  red  to 
brnh-red 

5HJJ 

4.9-5.3 

5  -5J 

Hex.  rhom.  ; 
comp.,  gran. 

F.  uneven, 
splint. 
P.  basal  or  rhom. 

Fe-blk. 

Rdh-brn. 
to  pur- 
plish-brn 

6  -7 

4.8-5.3 

5  -5J 

Iso.;  us.  oct. 
Fig.  1 

F.  conch. 
P.  oct. 

Dk.    brn.,    blk., 
yel. 

Yelh-brn. 

5  --51 

3.6-4.0 

5  -54 

Fibr.;  comp. 
botryoidal 

F.  splintery, 
uneven 

Yelh.    or    redh- 
brn.  to  blk. 

Yelh-brn. 

5  -54 

4.0-4.4 

5  -54 

Orth.;    acic.  or 
scaly  xls. 

C.  1,  pinac.,  per. 
F.  uneven 

Rdh-blk. 

Dk.  rdh-brn. 

5  £-6 

4.2-4.7 

5  -5J 

Botry.  ;  stalac., 
earthy 

F.  splintery, 
uneven, 
earthy 

Deep  red 

Brnh-red 

34-4 

5.8-6.1 

24-3 

Iso.;  comp. 

F.  uneven 

Fe-gry.  to  blk. 

Gryh-blk. 

3  -4 

5.8-6.2 

3 

Mon.;  earthy, 
comp.,  scaly 

F.  uneven 

Blk.,  brn.,  grn. 

Pearly, 
submet. 

2  -3 

2.7-3.1 

5 

Mon.,    pseudo- 
hex;  plates, 
scales 

C.  1,  basal,  per. 
Thin  flakes 
very  elastic 

Yelh-brn.,  grn. 

Pearly, 
submet. 

2  -3 

2.8-2.9 

44-5 

Mon.,    pseudo- 
hex;  plates, 
scales 

C.  1,  basal,  per. 
Thin  plates 
very  elastic 

Dk.  gryh-blk. 
to  brnh-blk. 

Blk. 

5  -54 

7.2-7.5 

3  -3} 

Mon.  ;  us.  xls. 

C.  1,  pinac.,  per. 
F.  uneven 

Blk. 

Brnh-blk. 

5 

7.5 

34 

Mon. 

C.  1,  pinac.,  per. 
F.  uneven 

Fe-blk.  to 
brnh-blk. 

Dk.  red 
to  blk 

6 

5.3-7.3 

5  -5} 

Orth.  ;  us. 
short  prism. 

C.  1,  pinac., 
poor 
F.  uneven,  conch. 

Velvet-blk. 

Dk.  rdh.- 
brn. 

5  -6 

5.6-5.8 

44-5 

Orth.;  us. 
comp., 
dissem. 

F.  conch. 

206 


SECTION  4.— Concluded.     Metallic  luster; 


Name. 

Composition. 

Gel.     sil.    in    HC1    sol.     on 
evaporation 

Fus.  w.  much  intumes. 
Insol.  in  HC1  after  fus. 

ALLANITE 
(Orthlte) 
(See  p.  71) 

(Ca,Fe)2(Al,Fe,Ce)3 
OH(Si04)3 

(Also  LI,  Nd,  Pr,  Y.'etc.) 

Strongly  mag.  after  fus. 
Little  intumea 

Ilvaite 
(Llevrltc) 
(See  p  22.) 

CaFe3(OH)(SiO4)2 

Te    minerals. 
Gently 
heated      in 
cone  H2SO4 
gives    rdh- 
violet  sol. 
(See  p.  188) 
(Mn  minerals 
distinguish 
ed  by  borax 
bd.  test) 

Fusible  and 
wholly  vol. 

Wh.  subl.  near  assay; 
grn.  flame 

Tellurium 
(See  p.  27) 

Te 

(Somct.  Se,  Au,  Fe) 

Ag  globule  in 
o.f. 

May  contain  also  Au; 
somewhat  sectile 

HKSSITE 
(See  p.  27) 

Ag2Te 
(Au  Iso.  w.  Ag) 

Au  w.  soda 
on  Ch.  Us. 
w.  some  Ag 

Slightly  sectile  to  brittle 

PETZITE 
(See  p.  14) 

Ag3AuTe2 

Very  brittle;  cleavable. 
Krennerite  decrepi- 
tates violently  b.b.  and 
fuses  to  Au  button 

SYLVANITE 
(See  p.  26) 

AuAgTe4 

KRENNERITE 
(See  p.  27) 

AuAgTe4 

Fuses  to  Au 
button 

Very  brittle  ;  uneven  to 
conchoidal  fract. 

CALAVERITE 
(See  p.  27) 

(Au,Ag)Te2 

Bi  w.  soda  on 
ch. 

Red  subl.  on  ch.  w.  von 
Kobell's  flux 

Tetradymite 

Bi2Te3 

(S  iso.  w.  Te) 

Pb  w.  soda 
on  ch. 

PbSO4  ppt.  w.  H2SO4  in 
HNO3  sol. 

Altaite 
(See  p.  28) 

PbTe 

(Some  Ag,  Au) 

Nagyagite 

Au,  Pb,  Sb,  Te,  S 

SECTION  5.     Metallic  luster: 


Strongly  mag.  be- 
fore heating.  (Cp. 
platinum,  which 
i  s  sometimes 
mag.) 

Completely  sol.  in  HC1;  sol.  reac. 
for  both  ferrous  and  ferric  Fe. 
(Cp.  ilmenite,  below) 

MAGNETITE 

(Magnetic  Iron  Ore; 
Lodestone) 
(See  p.  22) 

FeFe204 

(Somet.  Mg,  Mn,  Tl) 

Malleable.  Meteoric  Fe  and 
some  terrestrial  Fe  contains  Ni 

Iron 
(Native  Iron) 

Fe 
(Us.  w.  some  Nl) 

H2O2  test  for  Ti 

Somet.  slightly  mag. 

ILMENITE 
(Menaccanlte: 
Titanic  Iron) 
(See  p.  22) 

FeTiO3 
(Often  also  Fe»  Os;  somet. 

Mg) 

fus.  1-5  or  vol.;  no  As,  Sb,  nor  S 


207 


Color. 

Streak. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Brn.  to  piteh- 
blk. 

Gry. 

5  £-6 

3.0-4.2 

2* 

Mon.;  us. 
comp. 

F.  uneven 
conch. 

Fe-blk. 

Blk. 

.    5^-6 

4.0-4.1 

2* 

Orth.  us. 
prism,  xls. 

C.  2,  pinac. 
poor,  90°,  60°, 
120° 
F.  uneven 

Sn-wh. 

Sn-wh. 

2  -2i 

6.1-6.3 

1 

Hex.  rhom.;us., 
gran.,  comp. 

C.  3,  prism.,  per. 

Somewhat 
brittle 

Steel-gry  to 
Pb-gry. 

Gry. 

2£-3 

8.3-8.5 

1 

Iso.  ;  us.  comp. 

F.  uneven 

Steel-gry  to 
Fe-blk. 

Gry. 

2|-3 

8.7-9.0 

ii 

Comp.,  gran. 

F.  uneven 

Steel-gry  to 
Ag-wh. 

Gry. 

U-2 

7.9-8.3 

i 

Mon.  ;     branch- 
ing aggregates 

C.  1,  pinac.,  per. 
F.  uneven 

Ag-wh.  to 
brass-yell. 

Gry. 

2^ 

8.3-8.4 

i 

Orth;  us. 
prism., 
striated 

C.  1,  basal,  per. 
F.  uneven 

Pale  bronze- 
yel. 

Yelh-gry. 

2| 

9.0 

i 

Monocl.  ; 
us.  comp. 

F.  uneven,  conch. 

Pale  steel-gry. 

Gry. 

11-2 

7.2-7.6 

U 

Hex.  rhom.; 
us.  bladed 

C.  basal.,  per. 
Laminae  flex. 

Sn-wh.;  tar. 
bronze-yel. 

Gry. 

3 

8.1-8.2 

11 

Iso.  ;  us.  mass. 

C.  3,  cubic,  90° 
F.  uneven, 
sectile 

Dk.  Pb-gry. 

Dk.  Pb-gry. 

1  -11 

6.8-7.2 

11 

Orth.;  us.fol. 

C.  pinac.,  per.' 
Laminae  flex. 

fus.  above  5;    becomes  strongly  mag.  in  r.f. 


Fe-blk. 

Blk. 

5Mi 

4.9-5.2 

Iso.;    xls.,  oct., 
dodec., 
Figs.  1,  7,  8; 
gran. 

P.  4,  oct.,  701°, 

tool* 

F.  uneven, 
conch. 

Steel-gry. 

Steel-gry. 

4  -5 

7.3-7.8 

Iso.  ;  us.  mass. 

C.  cubic 
F.  hackly 

Fe-blk. 

Blk.  to 
brnh-red 

5  -6 

4.5-5.0 

Hex.  rhom.;  us. 
plates  or  mass. 

F.  conch. 
P.  basal,  rhom. 

208 


SECTION  5.— Concluded.     Metallic  luster; 


Name. 

Composition. 

Cr  in  s.ph.  bead 

Bead  shows  Fe  reac.  while  hot 
and  Cr  on  cooling 

CHROMITE 

(Chromic  Iron) 
(See  p.  133) 

FeCr204 
(Mglso.  w.Fe;  Aland 
Fe'"  Iso.  w.  Cr 

Mn  in  soda  bd. 

Wh.  ZnO  subl.  on  intense  ign.  w. 
soda  on  pt  wire;  grn.  w. 
Co(NO3)2.  (Fig.  81,  p.  189) 

FRANKLINITE 

(See  p.  23) 

(Fe.Zn.Mn) 
(Fe,Mn)2O4 

Not     in- 
clude  d 
above 

Little  or 
noH2O 
in  c.t. 

Sometimes  slightly  mag.  before 
heating.  Dif.  fus. 

HEMATITE 

(Specular  Iron) 
(See  p.  134) 

Fe203 
(Somet.  Tl,  Mg) 

Martite 
(See  p.  134)  . 

Fe203 

H2O   in 
c.t.  Dif. 
fus. 

Mammillary,  botryoidal,  stalac- 
titic,  amorphous 

LIMONITE 
(Brown  Hematite; 
Bog  Iron  Ore) 
(See  p.  131) 

FeO-OH-nH2O 

Us.  prisms.  ;  lepidocrocite  scaly 

GOETHITE 
(Lepidocrocite) 
(See  p.  142) 

FeO-OH 

Us.  decrepitates  violently  in  c.t. 

TUBGITE 
(Hydrohematlte) 
(See  p.  144) 

FeO-OH,Fe2O3,H2O 

SECTION  6.     Metallic  luster; 


Little    or    no    H2O 
in  c.t. 

O  in  c.t. 

PYROLUSITE 

(See  p.  18) 

MnO2 
(A  little  Hi  O) 

Slowly  sol.  in  HC1  w.  gel.  sil. 

Braunite 
(See  p.  23) 

3MnMnO3-MnSiO3 

No  gel.  sil. 

Hausmannite 
(See  p.  131) 

MnMn2O4 

Much  H2O  in  c.t. 

Prismatic  xls.,   us.  striated 

MANGANITE 
(See  p.  130) 

MnO-OH 

Amorphous;  us.  Ba  reac.  in  HC1 
sol.     Botry.,    reniform,    stalac- 
titic 

PSILOMELANE 

(See  p.  22) 

MnO2,MnO,H2O, 
BaO,K2O,  etc. 

Dull,  earthy,  frothy,  powdery,  or 
reniform  and  compact 

WAD 

(Bog  Manganese)              / 
(See  p.  17)                 .| 

MnO,  MnO2,H2O 
(Often  Fe,  SI.  Al.  Ba) 

fus  above  5;    becomes  strongly  mag.  in  r.f. 


209 


Color. 

Streak. 

Hard- 
ness. 

Specific 
Gravity. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Fe-blk.  to 
brnh-blk 

Dk.  brn. 

5* 

4.3-4.6 

Iso.;  gran., 
comp. 

F.  uneven,  conch. 

Fe-blk. 

Rdh-brn. 
to  blk. 

5|-6J 

5.1-5.2 

Iso.;  gran., 
comp.,  oct. 
xls.,  Fig.  1 

P.  oct. 
F.  uneven  conch. 

Steel-gry.  to 
Fe-blk. 
Earthy,  red 

Cherry-red 
brnh-red 

5Mi 

4.9-5.3 

Hex.  rhom.; 
comp.,  gran. 

F.  uneven,  splint. 
P.  basal,  rhom. 

Fe-blk. 

Purplish  or 
rdh-brn. 

6  -7 

4.8-5.3 

Iso.  ;  us  oct.  xls. 
Fig.  1 

P.  oct. 
F.  conch. 

Brn.  to  blk. 
Earthy,  yel. 

Yelh-brn. 
Yel.  ocher 

5  -5§ 

3.6-4.0 

No  xls.;  us. 
comp.  or  fibr., 
botryoidal 

F.  splintery,  uneven 

Dk.  brn.  to 
blk. 

Brnh-yel. 
to  ocher- 
yel. 

5  -5J 

4.0-4.4 

Orth.  ;  acic.  or 
scaly  xls. 

C.  1,  pinac.,  per 
F.  uneven,  splintery 

Blk  to 
rdh-blk. 

Brnh-red 

5  £-6 

4.2-4.7 

Botry.,  stalac., 
earthy 

F.  splintery,  uneven, 
earthy 

fus.  above  5;  not.  mag.  after  r.f.;  Mn  in  borax  bead 


Fe-blk. 

Blk. 

2  -2J 

4.7-4.8 

Pseudm.,  gran., 
columnar 

F.  splintery,  uneven 

Dk.  brnh-blk. 
to  steel-gry. 

Brnh-blk. 

6  -6J 

4.7^.8 

Tetr.;  us. 
pyram. 

C.  pyram.,  per. 
F.  uneven 

Brnh-blk. 

Chestnut- 
brn. 

5  -5J 

4.7-4.9 

Tetr.  ;  us.  gran.  ; 
pyram.  xls. 

C.  1,  basal 
F.  uneven 

Steel-grv.  to 
Fe-blk. 

Rdh-brn. 
to  blk. 

3J-4 

4.2-4.4 

Orth.;  prism., 
striated 

C.  1,  pinac.,  per. 
F.  uneven 

Fe-blk. 

Brnh-blk. 

5  -6 

3.7-4.7 

Amor.,  comp., 
botry. 

F.  uneven,  conch. 

Bluish  or 
brnh-blk.  to 
dull  blk. 

Brnh-blk. 
to  blk. 

1  -6 

3.0-4.3 

Amorph., 
earthy,  comp. 

F.  earthy 

210 


SECTION  7.     Metallic  luster;  fus.  above  5; 


Name. 

Composition. 

Very  soft.  Soils 
fingers  and 
marks  paper 
easily.  Greasy 
feel. 

S  and  Mo  reac.  in  o.t.  Yel-grn. 
flame.  Characteristic  gnh. 
streak  on  porcelain  or  glazed 
paper. 

MOLYBDENITE 
(See  p.  17) 

MoS2 

No  reac.  in  o.t.  Very  refractory 
b.b. 

GRAPHITE 

(Plumbago;  Black  Lead) 
(See  p.  17) 

C 
(Often  Fe,  clay,  etc.) 

Cr  in  borax  or  s. 
ph.  bd. 

Mag.  on  intense  ign.  w.  equal  amt. 
of  soda  on  ch.  (except  varieties 
with  much  Mg  and  Al) 

CHROMITE 

(Chromic  Iron) 
(See  p.  133) 

FeCr2O4 
(Mg  Iso.  w.  Fe;  Al  and 
Fe'"  Iso.  w.  Cr) 

H2O2  test  for  Ti  after 
fus.  w.  borax 

Mag.  on  intense  ign.  w.  equal  amt. 
of  soda  on  ch. 

ILMENITE 
(Menaccanlte: 
Titanic  Iron) 
(See  p.  22) 

FeTiO3 
(Some  Fe  O  and  Mg) 

Submetallic  to  adamantine  luster; 
us.  prismatic  xls. 

RUTILE 

(See  p.  72) 

TiO2 
(Us.  a  little  Fc) 

Similar  to  Rutile.  Disting.  by 
xl.  habit  and  phys.  properties. 
Brookite  us.  tabular  xls. 

Octahedrite 
(Anatase) 
(See  p.  68) 

Ti02 

Brookite 
(See  p.  72) 

Ti02 

Ca  reac.  in  HC1  sol.  after  fus.  w. 
soda  and  precipitating  Ti  w. 
am. 

Perovskite 
(Perofsklte) 
(See  p.  91) 

CaTiOa 
(Fe  Iso.  w.  Ca) 

Cb.  reac.  after  fus. 
w.  soda  or  borax, 
dissolving  in  HC1, 
and  boiling  w.  Sn. 

W.  little  soda  becomes  mag.;  us. 
Mn  reac.  also 

COLUMBITE 

(See  p.  134) 

(Fe,Mn)Cb2O6 
(Ta  Iso.  w.  Cb;  a  little  Sn. 
and  W) 

Tantalite 
(See  p.  134) 

(Fe,Mn)Ta2O6 
(Cb  Iso.  w.  Ta;  slight  Sn 
and  W) 

Disting.  by  st.  and  dull  exterior, 
brilliant  on  fresh  fracture 

Fergusonite 
(See  p.  133) 

(Y,Er,Ce,U) 
(Cb,Ta)O4 

U  in  s.  ph.  bd. 
Little  or  no  Cb 

Very  heavy;  sol.  in  dil.  H2SO4 
w.  slight  evolution  of  gas  (He) 

URANINITE 
(Pitchblende) 
(See  p.  22) 

Uranate  of  Pb  and  U 
(Also  Th,  La,  Y,  Ca,  N, 
He,  A,  and  us.  H2  O) 

Pt  or  metals  of  the 
Pt  group 

Malleable;  b.b.  unaltered;  some- 
times mag. 

PLATINUM 
(See  p.  29) 

Pt 
(Us.  w.  Fe,  Pd,  Rh.  Ir,  Os) 

Slightly  malleable  to  brittle;  Os 
in  o.t. 

Iridosmium 
(Osmlrldlum) 
(See  p.  29) 

Ir.Os 

(Somet.  Rh,  Pt,  Ru) 

No  reac.  for  Os 

Iridium 
(See  p.  29) 

Ir 
(W.  Pt,  Pd,  Rh) 

not.  mag.  after  r.f.;  no  Mn  in  borax  bead 


211 


Color. 

Streak. 

Hard- 
ness. 

Specific 

Gravity. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Pb-gry. 

Gryh-blk., 
grnh.  on 
glazed 
paper 

1  -li 

4.7-4.8 

Hex.  (?); 
foliated, 
scaly 

C.  1,  basal,  per.; 
thin  flakes, 
flex.  Sectile 

Fe-blk.  to  dk. 
steel-gry. 

Gryh-blk. 

1-2 

1.9-2.3 

Hex.  rhom.; 
foliated, 
earthy 

C.  1,  basal,  per.; 
thin  flakes, 
flex. 

Fe-blk.  to 
brnh-blk. 

Dk.  brn. 

5i 

4.3^.6 

Iso.;  us.  gran., 
comp. 

F.  uneven, 
conch. 

Fe-blk. 

Brnh-red 
to  blk. 

5  -6 

4.5-5.0 

Hex.  rhom.; 
us.  plates  or 
gran. 

F.  conch. 
P.  basal,  rhom. 

Rdh-brn.  to 
blk.  and  yelh. 

Pale  brn. 
to  gry. 

6  -7 

4.1-4.3 

Tetr.;us.  xls.; 
twins 

C.  2,  prism,  poor 
F.  uneven 

Brn.  to  dk. 
blue  and  blk. 

Wh. 

5J-6 

3.8-3.9 

Tetr.;  us. 
pyram., 
tabular 

C.  5.  basal  and  pyram, 
82°,  111°,  136*° 
F.  uneven 

Hair-brn  to  blk. 

Wh.  to 
gryh.  or 
yelh. 

5J-6 

3.9-4.1 

Orth.;  us.  xls. 
often  pseudo- 
hex. 

F.  uneven 

Yel.  and  brn. 
to  blk. 

Wh.  to 
gryh. 

5  £-6 

4.0 

Iso.,  cubes, 
Fig.  5;  stri- 
ated; dissem. 

C.  3,  cubic,  90° 
F.  uneven 

Fe-blk.  t6 
gryh.  and 
brnh-blk. 

Dk.  red 
to  blk. 

6 

5.3-6.5 

Orth.;  short 
prism,  xls. 

F.  uneven,  conch. 
C.  1,  pi  i  inc.,  poor 

Blk. 

Blk. 

6 

6.5-7.3 

Orth.;  short 
prism,  xls. 

F.  conch.,  uneven 
C.  1,  pinac.,  poor 

Brnh-blk 

Pale  brn. 

5i-6 

4.3-5.8 

Tetr.;  us. 
comp. 

F.  uneven 

Gryh.,  grnh., 
or  brnh-blk. 

Brnh-blk. 

5* 

9-9.7 

Iso.;  us.  botry., 
comp.,  gran. 

F.  conch. 

Whh.  steel-gry. 

Gry.,  shiny 

4  -4J 

14-19 

Iso.  ;  us.  grains 
or  scales 

F.  hackly 
mall.,  duct. 

Sn-wh.  to  It. 
steel-gry. 

Gry. 

6  -7 

18.9-21.2 

Hex.  rhom.;  us. 
flat  grains 

C.  1,  basal,  per. 
F.  uneven 

Ag-wh.,  tinge 
of  yel. 

Gry. 

6  -7 

22.6-22.8 

Iso.;  angular 
grains 

F.  hackly;   somewhat 
mall. 

212 


SECTION  8.     Nonmetallic  luster; 


Name. 

Composition. 

Burns  w.  blue  flame 
and  SO2  fumes 

Subl.  in  c.t.  is  red  liquid  while 
hot,  yel.  solid  when  cold 

SULPHUR 

(See  p.  94) 

s 

(Traces  Te,  Se,  As;  often 
clay,  bitumen,  etc.) 

As2O3  subl.  on  ch.  ; 
wh.  xln.,  vol.;  far 
from  assay 

Subl.  in  c.t.  deep  red,  nearly  blk. 
when   hot;     a   rdh-yel.    transp. 
solid  when  cold 
Orpiment,  thin  flakes  flexible 

REALGAR 
(See  p.  136) 

AsS 
(Slightly  sectlle) 

ORPIMENT 
(See  p.  136) 

As2S3 

Vol.  on  ch.;  AszOs,  subl.  in  c.t. 

Arscnolite 

As2O3 

SbzOa  subl.  on  ch.; 
dense  wh.  and 
near  assay 

SO2  in  o.t. 

Kermcsite 

Sb2S2O 

Easily  fus.  in  c.t.  w.  slight  wh. 
subl. 

Senarmontite 
(See  p.  49) 

Sb2O3 

Hg  subl.  in  c.t.  w. 
dry  soda 

SO2  and  Hg  in  o.t.;   blk.  subl.  in 
c.t. 

CINNABAR 

(See  p.  137) 

HgS 
(Us.    w.    FezOa.    clay, 
bitumen) 

Cl  reac.  w.  AgNO3  after  soda  fus. 

Calomel 
(See  p.  47) 

Hg2Cl2 

K  or  Na  flame  color; 
sol  in  H2O 

Alkaline  residue  after  ign.  ;  Wholly 
vol.  only  by  prolonged  heating 

See  Section  15, 
p.  224) 

Str.  Fe  -  black  to 
black 

Burns  w.  pale  feeble  flame 

ANTHRACITE  COAL 
(Hard  Coal) 
(See  p.  19) 

C,H,O,  etc. 

(C  85-95%) 

Str.  blk.  to  brnh- 
blk. 

Smoky  yellow  flame 

BITUMINOUS  COAL 
(Soft  Coal) 
(See  p.  19) 

C.H.O,  etc. 
(C  76-88%) 

Str.  brown  to  bnh- 
blk. 

Smoky  yellow  flame 

LIGNITE 
(Brown  Coal) 
(See  p.  128) 

C,H,O,  etc. 
(C  65-76%) 

Str.  h  n  h  -  b  1  k. 
Sticky  when  plas- 
tic 

Bright  flame  and  pitchy  odor 

ASPHALT 
(Mineral  Pitch) 
(See  p.  17) 

C,H,O,  etc. 

Str.  wh.  Electri- 
fied by  friction 

Dense  wh.  aromatic  fumes  on  ign. 

AMBER 
(Succinite) 
(See  p.  95) 

C20H3202 

Str.  bnh-yel.,  pale 
yel.     Plastic 

Smoky  yel.  flame,  paraffin  odor. 
Somet.  sticky 

OZOCERITE 
(Native  Paraffin) 
(See  p.  128) 

CnH2n+2 

easily  vol.  or  combustible 


213 


Color. 

Luster 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Pale  yel.  to 
brnh.  and 
grnh-yel. 

Resinous 

IMI 

2.0-2.1 

1 

Orth.; 
Figs.  34,  35 
gran.,  comp. 

F.  conch. 

Aurora-red  and 
orange-yel. 

Resinous 

1J-2 

3.556 

1 

Mon.;  gran, 
dissem. 

C.  1,  pinac. 
F.  conch. 

Lemon-yel. 

Resinous 
C.  pearly 

1J-2 

3.4-3.5 

1 

Mon.;  us.  fol. 

C.  pinac.,  per.; 
striated;  flex. 

Cols,  to  wh. 

Vitreous 
or  silky 

i* 

3.7 

1 

Iso.;  us.  capil. 

F.  uneven 

Cherry-red 
to  brnh-red 

Adamantine 

i  -H 

4.5-4.6 

1 

Mon.;  us.  acic. 

C.  pinac.,  per. 

Cols,  to  wh. 
and  gryh. 

Resinous 

2  -2* 

5.2-5.3 

H 

Iso.,oct.  Fig.  1; 
gran. 

F.  uneven 

Cochineal-red 
to  brnh. 

Adamantine 

2  -2* 

8.0-8.2 

Vol. 

li 

Hex.  rhom.; 
gran.,  earthy 

C.  3,  prism.,  per., 
60°,  120° 
F.  uneven 

Cols.,  wh., 
or  gry. 

Adamantine 

1  -2 

6.4-6.5 

Vol. 
1 

Tetr.;xls., 
coatings 

F.  conch. 
Sectile 

Fe-blk.  to  blk. 

Vitreous, 
submet. 

2  -2J 

1.3-1.7 

Amorph. 

F.  conch. 

Blk.  to 
bnh-blk. 

Pitchy,  dull 

2  -2| 

1.2-1.5 

Amorph. 

F.  cubical, 
conch. 

Bnh-blk 
to  blk. 

Dull 

2  -2£ 

1.1-1.4 

Amorph.,  often 
woody 

F.  conch., 
splint. 

Blk.  to 
bnh-blk. 

Pitchy,  dull 

1  -3 

1.0-1.8 

1 

Amorph. 

F.  conch. 

Yel.,  bnh., 
whitish 

Greasy, 
resinous. 

2  H* 

1.0-1.1 

1 

Amorph. 

F.  conch. 

Bnh-blk.,  yel., 
grn. 

Waxy, 
greasy, 
submet. 

1  -2 

0.9-1  0 

1 

Amorph. 

F.  uneven 

214 


SECTION  9.     Nonmetallic  luster;  fus  1-5; 


Name. 

Composition. 

COj  efferv.  in  warm 
dil.  acids 

In  c.t.  dark  yel.  while  hot;  de- 
crepitates 

CERUSITE 
(See  p.  51) 

PbCO3 

HC1  sol.  w.  BaCl2  gives  wh.  ppt. 
BaSO4;  slightly  sectile 

Leadhittite 
(See  p.  31) 

Pb4(OH)2(C03)2S04 

S.  reac.  in  fus.   w. 
soda;    sol.  in  dil. 
HC1;    PbCl2  ppt. 
on  cooling 

Little  or  no  H2O  in  c.t.  ;  decrepi- 
tates 

ANGLESITE 
(See  p.  40) 

PbSO4 

Canary-yel.  powder;  ferric  Fe 
and  Cu  in  HC1  sol. 

Beaverite 
(See  p.  135) 

CuPbFe2(OH)6 
(S04)2.H20 

HNO3  sol.  reacts  for 
P  w.  am.  mol. 

In  c.t.  slight  wh.  subl.  PbCl2 

PYROMORPHITE 

(See  p.  122) 

Pb6Cl(PO4)3 
(Often  also  Ca  and  As) 

As  subl.  in  c.t.  w.  ch. 

Wh.  ppt.  AgCl  w.  AgNO3  in 
HNO3  sol. 

MlMETITE 

(See  p.  97) 

Pb5Cl(AsO4)3 
(Often  also  Ca  and  P) 

V  in  s.  ph.  bead 

Wh.  ppt.  AgCl  w.  AgNOs  in 
HNO3  sol. 

VANADINITE 
(See  p.  96) 

Pb5Cl(VO4)3 
(Somet.  P  and  As) 

H2O  in  c.t.  Reacts  for  Zn. 
Cuprodescloizite  contains  Cu 

DESCLOIZITE 
(Cuprodesclolzlte) 
(See  p.  140) 

Pb2Zn(OH)VO4 
(Somet.  Cu,  As) 

Cr  in  s.  ph.  bead 

Streak  orange-yel.  Decrepitates 
on  ign. 

CROCOITE 
(See  p.  139) 

PbCr04 

Mo  in  s.  ph.  bead 

Streak  white.  Decrepitates  on 
ign. 

WULFENITE 

(See  p.  96) 

PbMoO4 
(Ca  somet.  Iso.  w.  Pb) 

SECTION  10.     Nonmetallic  luster;  fus.  1-5; 


Deep  red  color 
(  Hydrocuprite 
orange) 

Strong  sol.  in  HC1  gives  wh.  ppt. 
CuCl  when    much    diluted    (a 
cuprous  compound) 

CUPRITE 

(Hydrocuprite) 
(See  p.  141) 

Cu20 
(OH  In  hydrocuprlte) 

CO2  efferv.  in  HC1 

H2O  in  c.t. 

Disting.  by  color 

MALACHITE 
(See  p.  147) 

Cu2(OH)2CO3 

AZURITE 

(See  p.  147) 

Cu3(OH)2(CO3)2 

Blue  flame  col. 

H2O  in  c.t. 

ATACAMITE 
(See  p.  147) 

Cu2(OH)3Cl 

Pb  globule  w.  soda  and  ch.  on  ch. 


215 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Cols,  to  wh. 
and  gry. 

Adamantine 

3  -3J 

6.4-6.6 

1J 

Orth.; 
pseudohex. 

F.  conch- 

Cols.,  wh.,  yel., 
grn.,  or  gry. 

Resinous 
C.  pearly 

2| 

6.2-6.5 

11 

Mon.;  us.  tab.; 
comp. 

C.  1,  basal,  per. 
F.  uneven, 
conch. 

Cols.,  wh., 
yelh.,  grnh. 

Adamantine 
to  vitreous 

3 

6.1-6.4 

2\ 

Orth.;  us.  xls. 

C.  3,  basal  and 
prism.  76°,  90° 
F.  conch. 

Canary-yel. 

Dull 

1 

Hex.;  micro- 
scopic plates 

F.  earthy 

Grn.,  yel., 
bra.  and  wh. 

Resinous 

3M 

6.5-7.1 

2 

Hex.;  us. 
prism. 

F.  uneven 
conch. 

Cols,  yel., 
orange,  bra. 

Resinous 

3* 

7.0-7.3 

11 

Hex.;  prism.; 
crusts 

F.  uneven 

Ruby-red, 
bra.,  yel. 

Resinous 

3 

6.6-7.2 

H 

Hex.;  us. 
prism.  ;  Fig.  49 

F.  uneven, 
conch. 

Brnh-blk.  to 
red 

Greasy 

31 

5.9-6.2 

H 

Orth.;  us.  xls.; 
drusy 

F.  uneven, 
small  conch. 

Bright  red 

Adamantine 
to  vitreous 

2J-3 

5.0-6.1 

11 

Mon.  ;  us. 
prism. 

C.  2,  prism.,  86° 
F.  uneven, 
conch. 

Yel.,  orange- 
red,  gry.,  wh. 

Resinous  to 
ad  am  an- 
tine 

3 

6.7-7.0 

2 

Tetr.;  square 
tab. 

C.  pyram. 
F.  uneven 
conch. 

Cu  globule  w.  soda  and  ch.  on  ch. 


Ruby-red  to 
rdh-blk. 
(Orange) 

Adamantine 
to  earthy 

3|-4 

5.8-6.1 

3 

Iso.  ;  comp. 
(Hydrocuprite 
earthy) 

F.  uneven 

Bright  grn. 

Vitreous, 
silky,  or 
dull 

3M 

3.9-4.0 

3 

Mon.;  us. 
bo  try.,  incrust- 
ing. 

C.  1,  basal,  per. 
F.  conch., 
splint. 

Azure-blue 

Vitreous 

3*-4 

3.7-3.8 

3 

Mon.;  us.  xls.; 
incrust. 

C.  2,  domal,  29° 
F.  conch. 

Emerald-grn. 

Adamantine 
to  vitreous 

3  -3| 

3.7-3.8 

3^ 

Orth.;  us. 
prism. 

C.  1,  pinac.,  per. 
F.  conch. 

216 


SECTION   10.     Concluded.     Nonmetallic  luster; 


Name. 

Composition. 

S  reac.  in  fus.  w. 
soda 

Much  H2O  in  c.t.  Sol.  in  H2O 
Plates  moist  Fe  with  Cu 

CHALCANTHITE 
(See  p.  16) 

CuSO4-5H2O 

Acid  H2O  on  intense  ign.  in  c.t. 
Insol.  in  H2O 

BROCHANTITE 
(See  p.  147) 

Cu4(OH)6S04 

Canary-yel.  powder;  ferric  Fe 
and  Cu  in  HC1  sol. 

Beaverite 
(See  p.  135) 

CuPbFe2(OHe) 
(S04)2-H20 

Deflagrates  on  ch.  ; 
As  fumes  on  ch.; 
As  mirror  w.  ch. 
in  c.  t. 

Globule  xln.  after  fus.;  little 
H2O  at  red  heat 

Olivenite 
(See  p.  146) 

Cu2(OH)AsO4 

Decrep.  and  gives  much  H2O  in 
c.t.;  res.  of  olive-grn.  scales 

Chalcophyllite 

Cu7(OH)8(AsO4)2- 
10H2O 

SECTION  11.     Nonmetallic  luster;  fus.  1-5; 


Ag  globule,    brittle 
if    containing  Sb. 
SO2    fumes    and 
wh.  subl.  of  As2O3 
or  Sb2O3  in  o.t. 
(Cp.  polybasite) 

Abund.  subl.  in  c.t.,  deep  red  hot, 
rdh-yel.  cold;  slight  S  subl. 
above  it 

PBOUSTITE 

(Ruby  Sliver) 
(See  p.  137) 

Ag3AsS3 
(Somet.  Sb) 

Slight  subl.  in  c.t.,  blk.  hot,  red- 
brn.  cold;  slight  S  subl.  above 
it 

PYRARGYRITE 

(Ruby  Silver;  Dark  Ruby 
Silver) 
(See  p.  129) 

AgaSbSs 
(Somet.  As) 

Mall.  Ag  globule; 
Cl,  Br,  or  I  reac. 
w.  powdered  ga- 
lena in  c.t. 

Subl.  wh.  both  hot  and  cold. 
Highly  sectile  mineral 

CERARGYRITE 
(Horn  Silver) 
(See  p.  46) 

AgCl 
(Somet.  Hg  Iso.  w.  Ag) 

Subl.  yel.  hot,  wh.  cold.  Not 
disting.  by  bp.  methods.  Sec- 
tile 

EMBOLITE 
(See  p.  93) 

Ag(Cl.Br) 

Bromyrite 
(See  p.  95) 

AgBr 

Subl.  orange-red  hot,  lemon-yel. 
cold.  Sectile;  flakes  flex. 

lodyrile 
(See  p.  136) 

Agl 

Brittle  Bi  globule; 
red  subl.  w.  von 
Kobell's  flux 

CO2efferv.inHCl;  H2Oinc.t. 

Bismutite 

BiO-Bi(OH)2CO3 

fus.  1-5;  Cu  globule  w.  soda  and  ch.  on  ch. 


217 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Deep  azure- 
blue 

Vitreous 

21 

2.1-2.3 

3 

Tri.;  xls.,  crusts 
stalac. 

F.  conch. 

Deep  emerald 
grn. 

Vitreous 

3M 

3.9 

31 

Orth.;  us.  xls. 

C.  1,  pinac.,  per. 
F.  uneven 

Canary-yel. 

Dull 

1 

Hex.;  micro- 
scopic plates 

F.  earthy 

Blkh-grn.  to 
olive-grn. 
and  brn. 

Vitreous  to 
adaman- 
tine 

3 

4.1-4.6 

2-2* 

Orth.;  prism., 
fiber,  crusts 

F.  conch,  to 
uneven 

Grass-grn. 

Vitreous; 
C.  pearly 

2 

2.4-2.7 

2-21 

Hex.  rhom.; 
us.  tab. 

C.  basal,  per. 

Ag-wh.  globule  w.  soda  and  ch.  on  ch. 


Scarlet  to 
ruby-red 
St.  scarlet 

Adamantine 

2  -21 

5.5-5.6 

1 

Hex.  rhom. 
hemimor.  ; 
comp. 

C.  3,  rhom., 
poor,  72° 
F.  conch. 

Dk.  red  to  blk. 
St.  purplish 

Metallic 
adaman- 
tine 

21-3 

5.8-5.9 

1 

Hex.  rhom. 
hemimor.  ; 
comp.,  dissem. 

C.  3,  rhom., 
poor,  72° 
F.  conch., 
uneven 

Pearl-gry.  and 
grnh.  to  cols. 

Resinous 
to  ada- 
mantine 

1  -11 

5.5-5.6 

1 

Iso.;  us. 
wax-like 
crusts 

F.  uneven 
Sectile 

Grn.  or  yel. 

Resinous 
to  ada- 
mantine 

1  -11 

5.3-5.8 

1 

Iso.;  us.  comp. 

F.  uneven 
Sectile 

Grn.  or  yel. 

Resinous 
to  ada- 
mantine 

2  -3 

5.8-6.0 

1 

Iso.;  us.  comp. 

F.  uneven 
Sectile 

Yel.  to  grnh. 
and  brnh. 

Resinous 
to  ada- 
mantine 

1  -H 

5.6-5.7 

1 

Hex.  hemimor.  ; 
prisms,  scales 

C.  1,  basal,  per. 
Sectile 
Thin  flakes  flex. 

Wh.,  grn. 
yel.,  gry. 

Dull 

4-41 

6.8-7.7 

11 

Amorph., 
earthy 

F.  earthy 

218 


SECTION   13.     Nonmetallic  luster;  fus.  1-5;  no  metal  on 


Name. 

Composition. 

CO2  efferv.  in  hot  HC1 

Decrepitates;  becomes 
blk.  and  mag.  in  c.t. 

SIDERITE 
(Spathic  Iron) 
(See  p.  41) 

FeCO3 
(Mg,  Mn.  Ca  Iso.  w.  Fe) 

Dif  .  fus.  ;  strongly  mag.  after 
heating  in  r.f. 

Little  or  no  H2O  in  c.t.  ; 
st.  red 

HEMATITE 
(See  p.  134) 

Fe203 
(Somet.  Tl  and  Mg) 

Martite 
(See  p.  134) 

Fe2O3 

H2O  in  c.t.  Earthy, 
mammillary,  stalac- 
titic 

LIMONITE 
(Brown  Hematite) 
(See  p.  131) 

FeO-OH-nH2O 

Us.  prismatic  xls.  H2O 
in  c.t.  Lepidocrocite 
scaly 

GOETHITE 
(Lepidocrocite) 
(See  p.  142) 

FeO-OH 

Us.  decrepitates  in  c.t. 
H2O  in  c.t. 

TUBGITE 
(Hydrohematlte) 
(See  p.  144) 

FeO-OH,Fe203,H20 

Sol.  in  cold  H2O;    wh.  ppt. 
BaSO4  w.  BaCl2  in  HC1  sol. 
Acid  H2O  in  c.t.  The  ferric 
salts  give  Fe(OH)3  ppt.  in 
boiling  water 

Ferrous  iron  only;  yelh. 
on  exposure.  Sweet- 
ish astringent  metal- 
he  taste 

MELANTERITE 
(Copperas) 
(See  p.  120) 

FeSO4-7H2O 

(Mg  and  Mn  Iso.  w.  Fe) 

Ferric  iron  only.  Dis- 
agreeable  metallic 
taste 

COPIAPITE 

(See  p.  76) 

Fe4(OH)2(S04)6-17H20 
(Often  Al.Mg) 

Ferric  Fe  only;  K  flame; 
little  H2O  in  c.t. 

Jarosite 

KFe3(OH)6(SO4)3 
(NI  Iso.  w.  K) 

P  reac.  w.  am. 
mol.  Much 
ferrous  Fe 

Mn  in  borax 
bd.  Little  or 
no    H2O    in 
c.t. 

Li  flame. 
(Cp.  lithiophilite,  p.  228) 

Triphylite 

LiFePO4 
(Mn  Iso.  w.  Fe) 

F  reac.  w.  KHSO4 

Triplite 

R(RF)PO4 
(R  =  Fe,  Mn,  Ca.  Mg) 

Little    or    no 
Mn 

Whitens  w.  gentle  heat 
in  c.t. 

VIVIANITE 
(See  p.  104) 

Fe3(PO4)2.8H2O 

P     reac.      w. 
am.  mol. 

Ferric  Fe 

H2O  in  c.t. 

Dufrenite 

Fe2(OH)3P04 

As    subl.     in 
c.t.   w.   ch. 
fragment 

HC1   sol.   rose-red;     Co  in   borax   bd. 
after  roasting 
(Cp.  annabergite,  below) 

ERYTHRITE 
(Cobalt  Bloom) 
(See  p.  137) 

Co3(AsO4)2-8H2O 
(Nl,  Fe,  Ca  too.  w.  Co) 

HC1  sol.  grn.;    Ni  in  borax  bd.,  after 
roasting 
(Co  may  mask  bd.  reac.  for  Ni) 

ANNABERGITE 
(Nickel  Bloom) 
(See  p.  120) 

Ni3(AsO4)2-8H2O 
(Co  Iso.  w.  Nl) 

HC1   sol.   yel;    rdh-brn.   ppt.  w.   am.; 
ferric  but  no  ferrous  Fe 

SCORODITE 

(See  p.  122) 

FeAsO4-2H2O 

ch.;  mag.  after  r.f.;  sol.  in  HC1  without  res.  or  gel.  sil. 


219 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Lt.  to  dk.  brn. 
and  gry. 

Vitreous  ; 
C.  pearly 

3|-4 

3.8-3.9 

4H> 

Hex.  rhom.; 
gran.,  comp. 

C.  3,  rhom.,  per.,  73° 
F.  uneven 

Brnh-  red  to 
blk. 

Dull 

5M* 

4.9-5.3 

5  -5* 

Hex.  rhom.; 
earthy;  reni- 
form 

F.  uneven  to 
splint. 

Fe-blk. 

Submetallic 
to  dull 

6  -7 

4.8-5.3 

5  -5£ 

Iso. 

P.  4  oct.,  70£°,  109*° 
F.  conch. 

Yelh-brn  to 
dk.  brn 

Silky  or  dull 

5  -5| 

3.6-1.0 

5  -5| 

Fibr.,  bo  try., 
earthy 

F.  splint., 
uneven 

Yelh-  or  redh- 
brn.  to  blk. 

Adamantine 
to  dull 

5  -5* 

4.0-4.4 

5  -5J 

Orth.;  acic. 
or  scaly 

C.  1,  pinac.,per. 
F.  uneven, 
splint. 

Rdh-blk. 
St.  dk.  redh- 
brn. 

Dull,  silky 
to  sub- 
metal. 

5  -6 

4.2-4.7 

5  -5| 

Botry.,  incrust., 
stalac., 
earthy 

F.  splint., 
uneven, 
earthy 

Apple-grn  to 
wh. 

Vitreous 

2 

1.9 

1 
4^-5 

Mon.;  capil., 
fibr.,  comp. 

C.  1,  basal,  poor 
F.  conch., 
earthy 

S-yel. 

Pearly 

2* 

2.1 

4H3 

Mon.;  us. 
gran,  scales 

C.  1,  pinac. 
F.  uneven 

Ocher-yel.  to 
clove-brn. 

Vitreous 

2HH 

3.1-3.3 

4| 

Hex.  rhom.; 
us.  xls. 

C.  1,  basal 
F.  uneven 

Lt.  blue,  grn. 
or  gry. 

Vitreous  to 
resinous 

4J-5 

3.5-3.6 

H 

Orth.;  us. 
comp. 

C.  2,  basal,  per. 
and  pinac. 

Chestnut-brn. 
to  blkh-brn 

Resinous 

4H> 

3.4-3.8 

H 

Mon.;  us. 
comp. 

C.  2,  at  90° 
F.  uneven 

Blue,  bluish- 
grn.  to  cols. 

Vitreous; 
C.  pearly 

1^-2 

2.6-2.7 

2  -2h 

Mon.;  earthy, 
radial 

C.  1,  pinac.,  per. 
F.  splint., 
earthy 

Dull  olive  to 
blkh-grn. 

Silky,  weak 

3M 

3.2-3.4 

2* 

Orth.  us.  fibr. 

F.  splint. 

Crimson  to 
peach-red 

Dull;  vitre- 
ous; C. 
pearly 

l|-2i 

2  .  9-3  .  0 

2 

Mon.;  us. 
earthy,  acic. 

C.  1,  pinac.,  per.; 
sectUe 
Thin  flakes  flex. 

Apple-grn. 

Vitreous 

1  -2J 

3.0-3.1 

3 

Mon.;  us. 
earthy,  capil. 

F.  uneven 

Pale  grn  or  brn. 

Vitreous 

3|-4 

3.1-3.3 

2  -2$ 

Orth.;  us.  xls. 

F.  uneven 
conch. 

220 


SECTION   13.— Nonmetallic  luster;  f us.  1-5;  no  metal 


Name. 

Composition. 

Micaceous,  foliated,  or 
scaly.       Thin  flakes 
tough  and  elastic 

Gel.  sil.  w.  HC1  on  evapora- 
tion 

Lepidomelane 

(K,H)2Fe3(Fe,Al)4 
(Si04)3 

Slightly  sol.  in  HC1  w.  separa- 
tion of  SiO2 

BIOTITE 
(Black  Mica) 
(See  p.  58) 

(K,H)2(Mg,Fe)2 
Al2(SiO4)3 

Gel.  imperfectly;  iso. 
xls. 

Mostly  ferric  Fe 

ANDRADITE 
(Ca-Fe  Garnet) 
(See  p.  102) 

Ca3Fe2(SiO4)3 

(Fe,  Mn,  Mg,  Iso.  W. 
Ca;  Al  iso.  w.  Fe) 

Gel.  after  fus.  but 
not  before 

Partly  decomp.  by  HC1 

GLAUCONITE 
(Greensand) 
(See  p.119) 

KFe(SiO3)2H2O, 
approx. 

(Some  Al;  Mg) 

Gel.  ;  much  ferrous  Fe 

May  be  mag.  from  included 
magnetite 

Fayalite 
(See  p.  85) 

Fe2Si04 

(Some  Mn,  Mg) 

Gel.   ail.  w.  HC1;    both 
ferrous  and  ferric  Fe 

Fuses  quietly 

Ilvaite 
(Llevrlte) 
(See  p.  22) 

CuFe2(FeOH)  (SiO4)  2 

Fus.  w.  intumes 

ALLANITE 
(Orthlte) 
(See  p.  71) 

(Ca,Fe)2(Al)Fe,Ce)3 
(OH)(SiO4)a 
(Some  La.  Nd,  Pr.  Y. 
etc.) 

H2S  and  gel.  ml.  w.  HC1 

ZnO  subl.  on  ch.  w.  soda;  grn. 
w.Co(NO3)2.     (Seep.  189) 

Danaltie 

Gl3R4S(Si04)3 
(R=Mn,Fe.  Zn) 

SECTION  14.     Nonmetallic  luster;  fus.  1-5; 


Micaceous;  thin  flakes 
tough    and  flex,   or 
elastic 

Easily  fus.  ;  Li  flame 

Zinnwaldite 

(K,Li)3Fe(AlO)Al 
(F,OH)2(SiO4)3 

Dif.  fus. 

BIOTITE 

(Black  Mica) 
(See  p.  58) 

(K,H)2(Mg,Fe)2 
Al2(SiO4)3 

Red;  isometric 

Sol.  in  HC1  w.  gel.  after  fus. 

ALMANDITE 
(Fe-Al  Garnet) 
(See  p.  101) 

Fe3Al2(Si04)3 
(Mn,  Mg,  Ca  Iso.  w.  Fe) 

Fus.  quietly  or  w.  little 
intumes.  to  shiny  blk. 
glass 

(Concluded 
on  next  page) 

Little  or  no  Al. 
Diallage,  lamellar  to  fibr.,  w. 
pearly  to  metalloidal  luster 

PYROXENE 

(Diallage) 
(See  p.  Ill) 

Ca(Mg,Fe)(SiO3)2 

Hedenbergite 
(See  p.  Ill) 

CaFe(Si03)2 
(Some  Mg) 

on  ch.;  mag.  after  r.f.;  sol  in  HC1  w.  gel.  or  granular  sil. 


Color. 

Luster. 

Hard- 
ness. 

Specific. 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Blk.  to  grnh-blk. 

Adamantine 
to  pearly 

3 

3.0-3.2 

4H> 

Mon.,  6-sided 
plates 

C.  1,  basal,  per.; 
elastic 

Grn.  to  grnh. 
or  brnh-blk. 

Splendent; 
C.  pearly 

2-3 

2.8-3.1 

5 

Mon.,  often 
6-sided 

C.  1,  basal,  per.; 
elastic 

Wine-red,  grnh., 
yel.,  brn.,  to 
blk. 

Vitreous  to 
resinous 

6i~71 

3.8-3.9 

3| 

Iso.,dodecahedron 
and  trapezohe  - 
dron  common 

F.  uneven  to 
conch. 

Yelh-grn.  to 
gryh.  and 
blkh-grn. 

Vitreous, 
dull 

1-2 

2.2-2.4 

3-4 

Amorph.,  gran., 
earthy 

F.  earthy,  uneven 

Yel.  to  dark 
yelh-grn. 
and  blk. 

Metalloidal, 
resinous 

6* 

3.9-4.1 

4 

Orth.;  tabular, 
comp. 

C.  2,  pinac.,  90° 
F.  uneven 

Fe-blk. 

Submetallic 

5*-e 

4.0-4.1 

2* 

Orth.;  us. 
prism,  xls. 

C.  2,  pinac.,  poor, 
90° 
F.  uneven 

Brn.  to  pitch- 
blk. 

Resinous  to 
submetallic 

5^-6 

3.0-4.2 

2J 

Mon.;  us.  comp. 

F.  uneven,  conch. 

Flesh-red  to  gry. 

Vitreous  to 
resinous 

5J-6 

3.4 

3 

Iso.  tetrh.  ;  us. 
comp. 

F.  uneven 

no  metal  on  ch. ;  mag.  after  r.f. ;  insol.  in  HC1 


Gry.,  yel.,  brn., 
violet 

Pearly 

2-3 

2.8-3.2 

2J-3 

Mon.,  6-sided 
plates 

C.  1,  basal,  per.; 
flex. 

Grn.  to  grnh. 
or  brnh-blk. 

Splendent 
C.  pearly 

2-3 

2.8-3.1 

5 

Mon.,  6-sided 
plates 

C.  1,  basal,  per.; 
elastic 

Deep  red  to 
brnh-blk. 

Vitreous 

6.5-7.5 

3.9-4.2 

3 

Iso.,  dodecahe- 
drons and  trap- 
ezohedrons 
common 

F.  uneven  to  , 
conch. 

Lt.  to  dk.  grn. 

Vitreous 

5-6 

3.2-3.6 

4 

Mon.;  us.  xls., 
Figs.  40,  41 

C.  2,  prism.,  poor, 
87° 
F.  uneven 

Grn-blk.  to  blk. 

Vitreous 

5-6              3.5-3.6 

I 

2*-3 

Mon.  xls. 
Figs.  40,  41 

C.  2,  prism.,  poor, 
87° 
F.  uneven 

222 


SECTION   14.— Concluded.     Nonmetallic  luster;  fus. 


Name. 

Composition. 

Fus.  quietly  or  w.  little 
intumes.     to    shiny    blk 
glass.  —  Concluded. 

Often  Na  flame.  Contains 
Al  and  ferric  Fe 

AUGITE 

(See  p.  62) 

Ca(Mg,Fe)(SiO3)2 
(Alto  15-20%;  somet. 
Mn,  Na) 

HORNBLENDE 
(See  p.  61) 

Ca(Mg,Fe)3(Si03)4 
(Al  to  10-18%,  Na, 
and  often  H,  F) 

Na    flame;  fus.    quietly 

Prism  and  cl.  angles  near  90° 

Aegirite 
(Acmlte) 
(See  p.  63) 

NaFe'"(SiO3)2 

Quietly  and  dif.  fus. 

Us.  bronzy,  metalloidal  lus- 
ter; prism  and  cl.  angles 
near  90° 

HYPERSTHENE 
(See  p.  59) 

(Mg,Fe)SiO3 

Prism  and  cl.  angles  54°  and 
126°;  Fe  chiefly  ferrous; 
sometimes  fibrous  (asbes- 
tos) 

Anthophyllite 
(Asbestos  In  part) 
(See  p.  62) 

(Mg,Fe)SiO3 
(Somet.  also  Al) 

Fus.  w.  intumes. 

Fused  mass  dk.  brn.  or  blk.  ; 
gel.  w.  HC1  after  fus. 

EPIDOTE 

(Plstaclte) 
(See  p.  79) 

Ca2(AlOH)(Al,Fe)2 
(SiO4)3 

Pyroelectric.  Prismatic  xls. 
w.  curved  triangular  cross 
section 

TOURMALINE 

(Schorl) 
(See  p.  74) 

R9Al3(BOH)2(Si06)4 
R  =  Mg,  Fe,  Ca,  Na,  K, 
LI  (Often  a  little  F) 

Fus.  w.  intumes.  ; 
Na  flame 

Prism  and  cl.  angles  54°  and 
126°;  Fe  chiefly  ferrous 

Arfvedsonite 

(Na,K)2(Ca,Fe)SiO3 
(Some  Al.  Fe'") 

Both  ferrous  and  ferric  Fe, 
us.  fibrous 

CROCIDOLITE 
(See  p.  148) 

NaFe'"(Fe",Mg) 
(Si03)3 

Fus.  w.  difficulty  H2O  in 
c.  t.  on  intense  ign. 

Rosettes;     foliated;    thin 
scales 

Chloritoid 
(See  p.  60) 

H2FeAl2SiO7 

(Some  Mg,  somet.  Mn) 

Oblong  shining  scales  and 
plates 

Ottrelite 
(See  p.  60) 

H2(Fe,Mn)(Al,Fe)2 
Si209 

W  reac.  after  fus.  w. 
soda.     Very  heavy 

Mn  in  soda  bd. 

WOLFRAMITE 

(See  p.  21) 

(Mn,Fe)WO4 

Little  or  no  Mn  reac. 

FERBERITE 
(See  p.  21) 

FeW04 

(Some  Mn) 

1-5;  no  metal  on  ch.;  mag.  after  r.f. ;  insol.  in  HC1 


223 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Gnh-blk.  to  blk. 

Vitreous 

5-6 

3.2-3.6 

3-4 

Mon.  xls. 
Figs.  40,  41 
gran,  colum. 

C.  2,  prism.,  poor, 
87° 
F.  uneven 

Gnh-blk.  to  blk. 

Vitreous  to 
pearly 

5-6 

2.9-3.4 

3-4 

Mon.  prism, 
xls.,  gran. 

C.  2,  prism.,  per. 
56° 
F.  uneven,  splint. 

Grnh.  to  brnh- 
blk. 

Vitreous 

6-6.5 

3.5-3.6 

3.5 

Mon.;  prism. 

C.  2,  prism. 
F.  uneven 

Grnh-blk.  to 
brn.  and 
bronze 

Pearly  to 
bronzy 

5-6 

3.4-3.5 

5 

Orth.  ;  us.  mass. 

C.  2,  pinac.  per. 
F.  uneven 

Gry.  clove-brn., 
grn. 

Vitreous 
C.  pearly 

5.5-6 

3.1-3.2 

5-6 

Orth.;  us.  fibr. 

or  mass. 

C.  2,  prism,  per. 

Yelh.  to 
blkh-grn  and 

gry. 

Vitreous 

6-7 

3.2-3.5 

3-4 

Mon.;  us. 
prism. 

C.  1,  basal,  per. 
F.  uneven 

Blk.,  brn.,  grn. 

Vitreous  to 
resinous 

7-7J 

3.0-3.2 

3-5 

Us.  3 

Hex.  rhom. 
hemimor. 
Fig.  58 

F.  conch.,  uneven 

Blk.;  st.  dk. 
bluish-gry. 

Vitreous 

6 

3.4-3.5 

21 

Mon.;  us.  prism. 

C.  2,  prism.,  per. 
F.  uneven 

Leek-grn.  to 
deep  lavender- 
blue 

Silky,  dull 

4 

3.2-3.3 

3* 

Fibrous 

Fibrous 

Dk.  gry.,  grn., 
gnh-blk. 

Pearly 

6-7 

3.5-3.6 

5 

Tri.,  us.  foliated 
or  scaly 

C.  1,  basal,  per. 
Brittle 

Gnh-gry.,  blk 

Vitreous 

6-7 

3.2-3.3 

5 

Tri.,  oblong 
scales 

C.  1,  basal,  per. 
Brittle 

Gryh.  to  brnh- 
blk.;  st.  blk. 

Submetallic 

5-5  £ 

7.2-7.5 

4 

Mon.  ;  us.  xls 

C.  1,  pinac.  per. 
F.  uneven 

Blk.     St. 
brnh-blk 

Submetallic 

5 

7.5 

3| 

Mon.,  us.  xls. 

C.  1,  pinac.  per. 
F.  uneven 

224 


SECTION   15.     Nonmetallic  luster;  fus.  1-5;  no 


Make  flame  tests  below  with  Pt  wire.     Most  minerals  give    some  yellow  color  to  the  flame  after 

yellow.     The  violet  flame  of  K  is  purplish-red 


Name. 

Composition. 

Wh.  AgCl  ppt.  w. 
HNO3  sol.  and 
AgN03 

Wh.   BaSO4  ppt.    K  flame 
in  H2O  sol.   w. 
HC1  and  BaCl2. 

KAINITE 
(See  p.  39) 

KMgClSO4-3H2O 

bitter,       astrin-    Na  flame  ; 
gent  taste               salty  taste 

Hanksite 

9Na2SO4-2Na2CO3- 
KC1 

Intense  Na  flame  ;  no  S;  salty 
taste 

HALITE 

(Rock  Salt: 
Common  Salt) 

(See  p.  39) 

NaCl 
(Us.  also  Ca  and  Mg) 

K  flame,  Little  or  no  H2O  in 
no  S  c.t.;  salty,  bitter 

SYLVITE 
(See  p.  39) 

KC1 

(Na  Iso.  w.  K) 

Much  H2O  in  c.t.; 
bitter  taste;     ab- 
sorbs moisture 

CARNALLITE 
(See  p.  47) 

KMgC3-6H2O 

CO2  efferv.  w.  HC1. 
H2O  sol.  gives  alka- 
line reac.  w.  tur- 
meric paper 

Sol.  in  H2O  of  xln.  if  gently 
heated  in  c.t.  (H2O  =  63%) 
Alkaline  taste 

Natron 
(Sal  Soda) 

Na2CO3-10H2O 

H2O  and  CO2  when  gently 
heated  in  c.t.  ;  alkaline  taste 

TBONA 
(See  p.  32) 

HNa3(CO3)22H2O 

H2O  in  c.t.  ;  partly  sol.  in  H2O 

Gay-Lussite 

Na2Ca(CO3)2-5H2O 

Sulphates.  —  H2O  sol. 
w.  HC1  and  BaCl2 
gives  wh.  ppt.  BaSO4 

Much  H2O  in  c.t.;  fine  powder 
sol.  in  500  parts  H2O;  Ca 
flame 

GYPSUM 

(Selenlte) 
(See  p.  30) 

CaSO4-2H2O 

Na  flame;  little  or  no  H2O  in 
c.t. 

THENABDITE 
(See  p.  31) 

Na2,SO4 

B.b.  swells  and  gives  K  flame; 
H2O  sol.  w.  HC1  and  am. 
gives  gel.  ppt.  of  A1(OH)3 

Kalinite 
(Potash  Alum) 

KA1(SO4)2-12H2O 

Mg  reac.  w.  Co(NO3)2  on  ch. 
Bitter  salty  taste 

ErSOMITE 

(Epsom  Salt) 
(See  p.  49) 

MgSO4-7H2O 

Intense  Na  flame;  much  H2O 
in  c.t. 

MlRABILITE 
(Glauber  Salt) 
(See  p.  48) 

Na2SO4-10H2O 

Nitrates.  —  Deflagrate 
on  ch.;    NO2  fumes 
w.KHSO4inc.t. 
(Concluded  next  page) 

Intense  Na  flame;  cooling 
salty  taste 

SODA  NITER 
(See  p.  48) 

NaNO3 

metal  on  ch. ;  not  mag.  after  r.f . ;  alk.  after  ign. ;  sol.  in  water  225 

being  handled,  but  those   containing  Na  as  an  essential   constituent  give  an  intense  and  persistent 
when  seen  through  dark  blue  glass. 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Cols.,  wh.  to 
redh. 

Vitreous 

2*-3 

2.0-2.2 

li-2 

Mon.;  comp., 
gran. 

C.  3,  pinac.  and 
prism.,  39J°,  101° 

Cols.,  wh.  to 
yelh. 

Vitreous 

3  -3* 

2.5-2.6 

li 

Hex.  ;  us.  xls. 

C.  1,  basal 
F.  uneven 

Cols.,  wh., 
redh.,  bluish 

Vitreous 

2* 

2.1-2.6 

ti 

Iso.  ;  us.  cubic, 
Fig.  5; 
gran.,  comp. 

C.  3,  cubic,  per., 
90° 
F.  conch. 

Cols.,  wh., 
redh.,  bluish 

Vitreous 

2 

1.9-2.0 

li 

Iso.;  cubes, 
Fig.  5;  gran. 

C.  3,  cubic,  per., 
90° 
F.  conch. 

Cols.,  wh., 
redh. 

Vitreous 
to  greasy 

1 

1.6 

i-ii 

Orth.;  us.  mass. 

F.  conch. 

Cols.,  gry., 
wh.,  yelh. 

Vitreous 

i  -U 

1.4-1.5 

i 

Mon. 

C.  1,  basal 
F.  conch. 

Cols.,  gry., 
wh.,  yelh. 

Vitreous 

2i-3 

2.1-2.2 

u 

Mon.;  incrusting 

C.  1,  pinac.,  per. 
F.  uneven 

Cols.,  wh., 
yelh.,  gryh. 

Vitreous 

2  -3 

1.9-2.1 

li 

Mon.,  us.  xls. 

C.  2,  prism.,  per., 
111° 
F.  conch. 

Cols.,  wh., 
yel.,  red,  gray 

Vitreous 
C.  pearly 

H-2  • 

2.3-2.4 

3 

Mon.; 
Figs.  38,  39; 
gran.,  comp. 

C.  3,   prism,    and 
pinac.,  per.,  90°, 
66°,  114° 
F.  splint. 

Cols.,  wh., 
brnh. 

Vitreous 

2  -3 

2.7 

1.5-2 

Orth.;  xls.; 
cross-twins 

C.  1,  basal 
F.  uneven 

Cols,  or  wh. 

Vitreous 

2  -2J 

1.7 

1 

Iso.  pyr.  ;  us. 
fibr. 

F.  conch. 

Cols,  or  wh. 

Vitreous; 
earthy 

2  -2£ 

1.7-1.8 

1 

Orth.;  us.  fibr., 
gran. 

C.  1,  pinac.,  per. 
F.  conch. 

Cols,  or  wh. 

Vitreous 

H-2 

1.4-1.5 

ii 

Mon.;  us. 
crusts,  mealy 
efflores. 

C.  1,  pinac.,  per. 
F.  conch. 

Cols,  or  wh. 

Vitreous 

H-2 

2.2-2.3 

i 

1 

Hex.  rhom.; 
us.  incrust., 
gran. 

C.  3,  rhom.,  per., 
73i° 
F.  conch. 

226 


SECTION   15.— Concluded.     Nonmetallic  luster;  fus.  1-5;  no 


Name. 

Composition. 

Nitrates—  Concluded 

K  flame  ;  cooling  salty  taste 

NITER 
(Saltpeter) 
(See  p.  48) 

KNO3 

H2O  in  c.t.;  deliquescent  be- 
fore ign.  ;  taste  bitter 

Nitrocalcite 

Ca(N03)2-nH20 

B    reac.    w.    turmeric 
paper 

Swells  and  fus.  to  clear  glass; 
taste  sweetish  alkaline 

BORAX 
(Seep.  30) 

Na2B4O7-10H2O 

SECTION  16.     Nonmetallic  luster;  fus.  1-5;  no  metal 
Make  flame  tests  below  with  Pt  wire  and  HC1. 


CO2  efferv.  in 
dil.  HC1 

No  H2O  in  c.t.;  Ba  flame 

WITHERITE 

(See  p.  51) 

BaCO, 

H2O  in  c.t.;  alkaline  sol.  in  boiling 
H20 

Gay-Litssite 

Na2Ca(CO3)2-5H2O 

S  reac.  w.  pow- 
dered ch.  and 
soda  on  ch. 

Much  H2O  in 
c.t.    Readily 
sol.    in    hot. 
dil.  HC1 
(Cp.     anhy- 
drite, below) 

Sol.  in  500  parts  H2O; 
Ca  flame;   flakes  flex. 

GYPSUM 
(Selenlte: 
Alabaster) 
(See  p.  30) 

CaSO4-2H2O 

K  flame;  Mg  reac.  w. 
Na  phosphate; 
slight  bitter  astrin- 
gent taste 

Polyhalite 
(See  p.  78) 

K2MgCa2(SO4)4- 
2H2O 

Little    or    no 
H2O   in   c.t. 
A  nhydrite 
somet.  much 
H2O;        dis- 
tinguish  by 
H 

Na  flame;  sol.  inHCl; 
salty  taste 

Glauberite 
(See  p.  31) 

Na2Ca(SO4)2 

No  flame  col.  ;  slowly 
sol.  in  hot  dil.  HC1 

ANHYDRITE 

(See  p.  40) 

CaS04 

Sr  flame;  nearly  in- 
sol.  in  HC1 

CELESTITE 
(See  p.  40) 

SrS04 
(Somet.  Ca  and  Ba) 

Ba  flame;    nearly  in- 
sol.  in  HC1 
Decrepitates 

BARITE 

(Heavy  Spar) 
(See  p.  39) 

BaSO4 
(Somet.  Ca  and  Sr) 

F  reac.  w. 
KHSO4  and 
glass  in  c.t. 

Little    or    no 
H2Oinc.t. 

Na  flame;   easily  fus. 

CRYOLITE 
(See  p.  49) 

NasAlFg 

Ca  flame;  of  ten  phos- 
phoresces and  de- 
crepitates in  c.t. 

FLUORITE 
(Fluor  Spar) 
(See  p.  116) 

CaF2 
(Somet.  CI  Iso.  w.  F) 

metal  on  ch. ;  not  mag.  after  r.f . ;  alk.  after  ign. ;  sol.  in  water 


227 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Cols,  or  wh. 

Vitreous; 
silky 

2 

2.1-2.2 

1 

Orth.  ;  us.  crusts, 
acic. 

C.  2,  prism.,  per., 
70° 
F.  uneven 

Wh.  or  gry. 

Silky 

0  -1 

2 

Fibrous,  efflores. 

Fibrous 

Cols.,  wh., 
gryh. 

Vitreous  to 
resinous 

2  -2£ 

1.7 

i-ii 

Mon.  ;  us.  comp. 

C.  1,  pinac.,  per. 
F.  conch. 

on  ch. ;  not  mag.  after  r.f. ;  alk.  after  ign. ;  insol.  in  water 


Cols.,  wh., 
yelh.,  gryh. 

Vitreous 

3  -4 

4.3-4.4 

2 

Orth.  twinned 
pseudohex. 

F.  uneven 

Cols.,  wh., 
yelh.,  gryh. 

Vitreous 

2  -3 

1.9-2.0 

11 

Mon.;  us.  xls. 

C.  2,  prism.,  per., 
111° 

Cols.,  wh., 
yel.,  red,  gry. 

Vitreous 
C.  pearly 

H-2 

2.3-2.4 

3 

Mon., 
Figs.  38,  39; 
gran.,  comp. 

C.  3,  prism.,  pinac., 
per.,  90°,  66° 
F.  conch.,  splint. 

Brick-red  to 
yel.  and  wh. 

Vitreous  to 
resinous 

2*-3 

2.7-2.8 

a 

Mon.;  fibr., 
lamel. 

C.  1,  pinac. 
F.  splint. 

Cols.,  wh., 
yelh.,  gryh. 

Vitreous 

21 

2.7-2.8 

11-2 

Mon.;  us.  tab. 
and  xls. 

C.  1,  basal,  per. 
F.  conch. 

Cols.,  wh., 
blue,  gry., 
red 

Vitreous; 
basal  cl., 
pearly 

3  -3£ 

2.9-3.0 

3 

Orth.;  us.  mass. 

C.  3,  pinac.,  per., 
90° 

Cols.,  wh., 
blue,  red 

Vitreous  to 
pearly 

3  -3* 

3.9-4.0 

3 

Orth.,  Fig.  37 
xls.,  fibers 

C.  3,  basal,  per. 
and  prism.,  76°, 
90° 

Cols.,  wh., 
blue,  yel., 
red,  brn. 

Vitreous  to 
pearly 

2HH 

4.3-4.6 

3 

Orth.,  xls., 
comp. 
lamellar 

O.  3,  basal,  per. 
and  prism.,  78%°, 
90° 

Cols.,  wh., 
brnh. 

Vitreous  to 
greasy 

21 

2.9-3 

li 

.Mon.;  us.  gran., 
comp. 

F.  uneven 
P.  3,  often,  88°, 
90° 

Cols.,  violet, 
blue,  grn., 
yel.,  pink 

Vitreous 

4 

3.0-3.2 

3 

Iso.  ;  us.  cubes, 
Fig.  5 

C.  4,  oct.,  per., 
70J°,  109£° 
F.  uneven 

228 


SECTION  17.     Nonmetallic  luster;  fus.  1-5;  no  metal  on  ch.;  not 


Name. 

Composition. 

H2S  efferv.  in 
hot  HC1 

Wh.  ZnO  subl.  after  intense  ign.  w.  soda 
on  Pt.  wire;  subl.  grn.  w.  Co(NO3)2 
(See  p.  189) 

SPHALERITE 

(Zinc  Blende) 
(See  p.  88) 

ZnS 
(Fe.  Mn,  Cd  Iso.  w.  Zn) 

Wurtzite 
(See  p.  130) 

ZnS 
(Some  Fe) 

P     reac.     w. 
am.  mol. 

Slight  F  reac. 
w.  KHSO4 
in  c.t. 

CaSO4  ppt. 
w.   H2SO4 
in  HC1  sol. 

No  H2O  in 
c.t. 

APATITE 

(See  p.  98) 

Ca5F(P04)3 
(Cl  Iso.  w.  F) 

A  little  H2O; 
HF  vapor 
in  c.t. 

Herderite 

CaGl(OH,F)PO4 

Mn  in  soda 
bd. 

Li  flame 

(Cp.  triphy- 
lite),p.  218 

Lithiophilite 

LiMnP04 
(Fe  Iso.  w.  Mn) 

H2O  in  c.t. 

No  flame  col- 
or 

Purpurite 

2(Fe,Mn)PO4-H2O 

U  in  s.  ph. 

bd. 

CaSO4  ppt.  w.  dil.  H2SO4 
in  HC1  sol. 

Autunite 
(See  p.  138) 

Ca(U02)2(P04)2- 
8H2O 

B     reac.     w. 
turmeric 
paper 

Na  flame 

Swells;  sol.  in  H2O 

BORAX 
(See  p.  30) 

Na2B4O7-10H2O 

Ca  reac.  w.  am.  oxalate 

ULEXITE 
(Boronatrocalclte) 
(See  p.  46) 

NaCaB6O9-8HO 

B  flame 

No  H2O  in  c.t.;    Cl  reac. 
after  fus.  w.  soda 

BORACITE 

(See  p.  56) 

Mg7Cl2Bi6O3o 

Slowly  vol.;    sol.  in  H2O 
small  scales;  greasy  feel 

Sassolite 
(  Boric  Acid) 
(See  p.  29) 

H3B03 

Mn  in  borax  bd. 

Stissexite 

H(Mn,  Mg,Zn)BO3 

Decrepitates,      exfoliates; 
Ca  reac.  in  dil.  sol.  w. 
am.  oxalate 

COLEMANITE 

(See  p.  34) 

HCa(BO2)3-2H2O 

Mo  reac.  in  s.ph.  bd.  or  H2SO4;  H2O  in  c.t.;  on  ch.  fus. 
and  M.  .(  ),  subl. 

Molybdite 
(See  p.  92) 

Fe2(MoO4)3-7|H2O 

Yel.  powder  or  earthy  mass  ;  greasy  feel  ;  V  in  s.ph.  bd.  ; 
H2O  in  c.t.  ;  fus.  easily  to  blk.  non-mag,  slag 

CARNOTITE 
(See  p.  135) 

(K2,Ca)O-2U2O3- 
V2O5-nH2O 

As    subl.    w. 
soda    and 
ch.  in  c.t. 

CaSO4  ppt.  w.  H2SO4  in  cone.  HC1  sol. 
Sectile;  thin  flakes  flex. 

Pkarmacolile 
(See  p.  49) 

HCaAsO4-2H2O 

mag.  after  r.f.;  not  alk.  after  ign.;  sol.  in  HC1  without  res.  or  gel.  sil. 


229 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Wh.,  grn.,  yel., 
red,  brn.,  blk. 

Res.  to 
adamant 

8|-4 

3.9-4.1 

5 

Iso.  tetr.  ;  gran., 
comp. 

C.  6,  dodec.  per., 
60°,  90°,  120° 
F.  conch. 

Bnh-blk. 

Resinous 

3M 

3.9-4.0 

5 

Hex.  hemimor.  ; 
fibr. 

F.  uneven, 
splintery 

Grn.,  blue, 
violet,  red, 
brn.,  cols. 

Vitreous  to 
greasy 

4  Hi 

3.1-3.2 

5-5  £ 

Hex.,  us. 

prisms 

C.  1,  basal,  poor 
F.  uneven,  conch. 

Wh.  to  pale  grn. 
or  yel. 

Vitreous  to 
resinous 

5 

3.0 

4 

Mon. 

F.  uneven 

Salmon-color, 
yel.  to  brn. 

Vitreous  to 
resinous 

4H> 

3.4-3.5 

H 

Orth.  ;  us.  mass. 

C.  2,  basal,  per.  and 
pinac. 

Deep  red  or 
redh-purple 

Silky 

4  -41 

3.4 

3-4 

Orth.(?);  us. 
mass. 

C.  2,  pinac.  90° 
F.  uneven 

Lemon-yel. 
to  S-yel. 

Adamant. 
C.  pearly 

2  -2| 

3.1-3.2 

2| 

Orth.;  tabular, 
pseudotetr. 

C.  1,  basal,  per., 
flakes  brittle 

Cols.,  wh., 
gryh.,  bluish, 
grnh. 

Vitreous  to 
resinous 

2  -2i 

1.7 

1-lJ 

Mon.;  us.  comp. 

C.  1,  pinac.,  per. 
F.  conch. 

Wh. 

Silky 

0  -1 

1.6-1.7 

1 

Mon.  ;  fibrous 

Very  fragile 

Cols.,  wh.,  yel., 
gry.,  grn. 

Vitreous 

7 

2.9-3.0 

2 

Iso.  tetrh.;  us; 
isolated  xls. 

F.  conch,  uneven 

Cols.,  wh.,  yel., 
gry. 

Pearly 

1 

1.4-1.5 

i 

Tri.;  small  scales 

C.  1,  basal,  per. 
greasy  feel 

Wh.,  yelh., 
pinkish 

Silky 

3 

3.4 

2 

Orth.(?);  fibr. 

F.  splint. 

Cols.,  wh., 
yelh.,  gryh. 

Vitreous  to 
adamant. 

4  -4| 

2.3-2.5 

Ii 

Mon.;  prism, 
xls.;  gran. 

C.  2,  pinac.,  per., 
90° 
F.  uneven,  conch. 

Straw-yel.  to 
wh. 

Silky  to 
adamant  ; 
C.  pearly 

1  -2 

4.5 

2 

Orth.;  earthy, 
crusts 

C.  1,  basal 

Canary-yel. 

Dull 

0  -1 

2J 

Hex.(?);  us. 
earthy 

Wh.,  gryh., 
redh. 

Vitreous  to 
pearly 

2  -2J 

2.6-2.7 

2* 

Mon.;  us.  fibr. 
crusts,  powder 

C.  1,  pinac.,  per. 
F.  uneven 

230 


SECTION  18.     Nonmetallic  luster;  f us.  1-5;  no  metal  on  ch.;  not 


Name. 

Composition. 

Fus.  quietly  to  cols, 
glass 

Whitens  in  c.t.;  Na  flame  w. 
gypsum 

NATROLITE 

(See  p.  35) 

Na2Al(AlO)(SiO3)3- 
2H2O 

Fus.  with  intumes- 
cence 

To  cols,  glass;  B-flame 

DATOLITE 
(See  p.  53) 

Ca(BOH)SiO4 

To  blebby  glass;  CO2  efferv.  in 
HC1 

CANCRINITE 
(See  p.  91) 

H6Na6Ca(NaCO3)2 
Al8(SiO4)9 

To  wh.  blebby  enamel  ;  Na  flame 
w.  gypsum  ;  pyroclectric 

THOMSONITE 
(See  p.  53) 

(Ca,Na2)2Al4(SiO4)4- 
5H20 

To  voluminous  frothy  slag;  py- 
electric 

Scolecite 
(See  p.  36) 

CaAl(AlO)(SiO3)3- 
3H2O 

To  wh.  blebby  enamel;  Na  flame 
w.  gypsum;  not  pyroelectric 

Mesolite 

Na2Ca2Al3(AlO)3 
(SiO3)9-8H2O 

To  white  blebby  enamel  ;  not  py- 
electric 

LAUMONTITE 
(See  p.  41) 

H4Ca(AlO)2(SiO3)4- 
2H2O 

SECTION   19.     Nonmetallic  luster;  f  us.  1-5;  no  metal  on  ch.;  not  mag. 


Efferv.  of  H2S  in 
HC1 

Na  flame;    BaSO4  ppt.  w.  BaCI2 
in  HC1  sol. 

LA  zu  RITE 
(Lapis  Lazuli) 
(See  p.  148) 

NaBAl3S3(SiO4)3 

ZnO  subl.  w.   soda  on   Pt  wire 
(See  p.  189) 

Danalite 

Gl3R4(SiO4)3 
(R=Mn,  Fe,  Zn) 

AgCl       ppt.      w. 
AgNO3  in  HNO3 
sol.;  Na  flame 

Fus.  to  cols,  glass 

SOD  A  LITE 

(See  p.  124) 

Na4Al3Cl(Si04)3 

Fus.  to  opaq.  grnh.  bd.;   Zr  reac. 
w.  turmeric  paper 

Eudialyte 
(Eucolitc) 

Na4Ca3Zr(SiO3)7 
(Some  K,  H,  Fe.  Mn: 
Ce,  Cl) 

Wh.  BaSO4  ppt.  w. 
Bad,  in  dil.  HC1 
sol. 

Contains  much  Ca  (Ppt.  Si  and 
Al  first).     See  Silicon  (2),  p.  185 

Hauynite 
(Tlauyne) 

CaNa:tAl3(SO4)  (SiO4)3 

Contains  little  or  no  Ca 

No8«lile 

(Nosean) 

Na5Al3(SO4)(SiO4)3 

Mn  in  borax  bd. 
Cp.  willemite, 
below) 

Wh.  ZnO  subl.  in  fine  powder  w. 
soda    on    Pt.    wire;     grn.    w. 
Co(NO3)2.     (See  p.  189) 

TROOSTITE 
(See  p.  90) 

(Zn,Mn)jSiO4 

Little  or  no  Zn  ;  gel.  in  cold  HC1 

TEPHROITE 
(See  p.  63) 

Mn2SiO4 

(Some  Mg,  Fe) 

mag.  after  r.f.;  not  alk.  after  ign.;  sol.  in  HC1  w.  gel.  sil.;  water  in  c.t. 


231 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Cols.,  wh., 
yelh.,  redh., 
grnh. 

Vitreous  to 
pearly 

5  -5J 

2.2-2.3 

2 

Orth.  ;  prism., 
pseudotetrag, 
radial,  fibr. 

C.  2,  prism.,  per., 
89° 
F.  uneven 

Cols.,  grnh., 
yelh.,  redh. 

Vitreous 

5  -5}- 

2.9-3.0 

2-2  .  5 

Mon.;  us.  xls.; 
gran. 

F.  conch,  to 
uneven 

Yd.,  pink, 
grnh.,  bluish, 
gry.,  wh. 

Vitreous  to 
greasy 

5  -6 

2.4-2.5 

2 

Hex.  ;  us.  comp. 

C.  3,  prism.,  60°, 
120° 
F.  uneven 

Cols.,  wh., 
grn.,  brn., 
gry- 

Vitreous  to 
pearly 

5  -5| 

2.3-2.4 

2 

Orth.  ;  us.  radial, 
fibr. 

C.  2,  pinac.,  per., 
90° 
F.  uneven 

Cols.,  or  wh. 

Vitreous  or 
silky 

5  -5J 

2.2-2.4 

2.5 

Mon.;  us. 
slender 
radiated 

C.  2,  prism.,  88J° 
F.  splint., 
uneven 

Cols.,  wh., 
gry.,  yel. 

Vitreous  to 
silky 

5 

2.2-2.4 

2-2.5 

Mon.;  acic. 

C.  2,  prism.,  per. 

Wh.,  yelh., 
gryh.,  redh. 

Vitreous 
C.  pearly 

3.5-4 

3.2-3.3 

2.5 

Mon.;  prism., 
radial 

C.  3,  pinac.  and 
prism.,  per., 
9.6°,  94°,  137° 
F.  uneven 

after  r.f.;  not  alk.  after  ign.;  sol.  in  HC1  w.  gel.  sil.;  little  or  no  water  in  c.t. 


Deep  azure  to 
grnh-blue 

Vitreous 

5  -5| 

2.4-2.5 

3 

Iso.;  comp.;  xls., 
Fig.  7,  dodec. 

C.  6,  dodec.  60°, 
120°,  poor 
F.  uneven 

Flesh-red  to 
gry. 

Vitreous  to 
resinous 

5M 

3.4 

3 

Iso.  tetrh.; 
us.  mass. 

F.  uneven 

Wh.,  gry., 
blue  grn., 
redh. 

Vitreous  to 
greasy 

5  -6 

2.1-2.3 

3M 

Iso.;  comp., 
dissem. 

C.  6,  dodec.,  60°, 
90°,  120° 
F.  conch.,  uneven 

Rose,  brnh-red, 
brn. 

Vitreous 

5  -5| 

2.9-3.0 

3 

Hex.  rhom. 

C.  1,  basal,  per. 
F.  splint. 

Blue,  grn., 
red,  yel.,  wh. 

Vitreous 

5M 

2.  4-2  '.5 

*i 

Iso. 

C.  6,  dodec. 
F.  uneven 

Gry.,  grn., 
blue,  brn., 
blk. 

Vitreous 

51 

2.2-2.4 

3i-4 

Iso. 

F.  uneven 

Apple-grn., 
flesh-red, 
brn. 

Vitreous 

5J 

4.1-4.2 

4-4* 

Hex.  rhom.; 
us.  mass. 

C.  3, 

prism.,  60°,  120° 
F.  uneven 

Smoky-gry., 
brnh-red 

Vitreous  to 
greasy 

5  £-6 

4.0-4.1 

3-3$ 

Orth.;  us. 
gran.,  comp. 

C.  2,  pinac.,  90° 
F.  uneven,  conch. 

232 


SECTION  19.— Concluded.     Nonmetallic  luster;  f us.  1-5;  no  metal  on  ch.;  not 


Name. 

Composition. 

ZnO   subl.   w.   soda 
on  Pt  wire 
(See  p.  189) 

May  also  contain  Mn 

WlLLEMITE 

(See  p.  90) 

Zn2SiO4 
(Often  Mn.  Fe) 

Contain  Si,  Al,  and 
Ca.     See     Silicon 
(2),  p.  185 

Easily  sol.  in  HC1;   Na  flame 

NEPHELITE 
(  Elaeollte) 
(See  p.  44) 

Approx.  NaAlSiO4 
(Some  K  and  Ca) 

Dif.  sol.  in  HC1;    Na  flame  w. 
powdered  gypsum;  fus.  to  cols, 
glass 

ANOKTHITE 
(Lime  Feldspar) 
(See  p.  37) 

CaAl2(SiO4)2 

(Some  Na) 

Fus.  w.  intumes.  to  dark  slag 

ALLAN  ITE 
(Orthlte) 
(Seep.  71) 

(Ca,Fe)2(Al,Fe,Ce)3 
(OH)(Si04)3 
(Also  La,  Nd.  Pr.  Y, 
etc.) 

Fus.  w.  slight  intumes.  to  grnh. 
or  yelh.  glass 

Melilite 

Nas(Ca,Mg)u 
(Al,Fe)4(SiOO» 

Ti  w.  H2O2 

Gel.  ail.  in  HC1 

Schorlomite 
(See  p.  102) 

Ca3(Fe,Ti)2(Si,Ti)4Oi2 

Not  included  above 

Swells  and  cracks  apart  on  ign.  ; 
often  glows  ;  str.  gnh-gry. 

Gadolinite 
(See  p.  73) 

FeGli(YO),(Si04). 

SECTION  20.     Nonmetallic  luster;  fus.  1-5;  no  metal  on  ch.;  not  mag.  after 


Micaceous;  flex., 
but  not  elastic,  or 
little  so 

Exfoliates  greatly  b.b.     Hy- 
drated  mica 

VERMICULITE 
(Jefferlslte) 
(See  p.  75) 

Hydrous  Mg-Fe-Al 
silicate 
(Somet.  Na,  K) 

Dif.  fus.;  little  or 
no  Al  or  Ca; 
much  Mg.  See 
Silicon,  (2)  p.  185 

Us.  compact  grnh.  mass.;  some- 
times fibrous  (chrysotile,  com- 
mercial "asbestos")  or  foliated 
(marmolite) 

SERPENTINE 

(Chrysotlle;  Marmolite) 
(See  p.  122) 

H4Mg3Si209 
(Some  Fe,  somet.  Nl) 

Somewhat  like  a  gum  or  resin 

DEWETLITE 
(Gymnltc) 
(See  p.  50) 

H4Mg4(SiO4)3.4H2O 
(Somet.  Nl) 

Compact,  fine  earthy  texture; 
when  dry  floats  on  H2O 

SEPIOLITE 
(Meerschaum) 
(See  p.  49) 

H4Mg2Si3O]0 
(Somet.  Cu  and  Nl) 

Whitens  and  fus. 
quietly 

To  clear  glass;  Na  flame 

ANALCITE 
(See  p.  53) 

NaAl(SiO3)rH2O 

To  translucent  glass;  BainHCl 

HARMOTOME 
(See  p.  34) 

H2Ba,Al2(SiO3)6- 
4H2O 

To  blebby  wh.  enamel.;  K  flame 
w.  gypsum 

Phillipsite 
(See  p.  34) 

(Ca,K2)Al2(SiO,)4. 
5H2O 

mag.  after  r.f.;  not  alk.  after  ign.;  sol.  in  HC1  w.  gel.  sil.;  little  or  no  water  in  c.t. 


233 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Yel.,  red,  grn., 
brn.,  wh., 
cols. 

Vitreous 

5  -6 

3.9-4.2 

3M 

Hex.  rhom.; 
comp.,  gran., 
dissem. 

C.  3.  basal  and 
prism.,  60°,  120° 
F.  uneven,  conch. 

Cols.,  gry., 
grnh.,  redh., 
yelh. 

Vitreous  to 
greasy 

5  -6 

2.5-2.6 

3* 

Hex.  hemi- 
morph.  ; 
comp.,  gran. 

C.  3,  prism.,  60°, 
120° 
F.  uneven,  conch. 

Cols.,  wh., 
gry.,  redh. 

Vitreous 

6  -6£ 

2.7-2.8 

4* 

Tri.,  prism,  xls., 
cleav.,  comp. 

C.  2,  basal.,  per. 
and  pinac.,  87° 
F.  uneven 

Brn.  to  blk. 

Res.,  vitr.  to 
submet. 

5^-6 

3.0-4.2 

2* 

Men.;  us.  mass. 

F.  uneven,  conch. 

Grn.,  yel., 
brn.,  wh. 

Vitreous  to 
resinous 

5 

2.9-3.1 

3 

Tetr.;  us.  xls. 

C.  1,  basal 
F.  uneven 

Blk. 

Vitreous 

7  -7J 

3.8-3.9 

3 

Iso.;  comp. 

F.  conch. 

Grnh.  to 

brnh-blk. 

Vitreous  to 
greasy 

6  -7 

4.0-4.5 

5 

Mon.;  comp., 
gran. 

F.  conch.,  splint. 

r.f.;  not  alk.  after  ign.;  decomposed  by  HC1  w.  separation  of  sil.;  water  in  c.t. 


Yel.,  brn.,  It.  to 
dk.  grn. 

Pearly 

i-H 

2.3-2.8 

3* 

Mon.;  fol., 
scaly,  flaky 

C.  1,  basal,  per. 
Thin  flakes  flex., 
not  elastic 

Olive  to  blkh- 
grn.,  yelh- 
grn.,  wh. 

Greasy, 
wax-like, 
silky 

3-4 

2.5-2.6 

5-5  £ 

Mass.  ;  pseu- 
domorphous, 
fibrous 

F.  uneven,  splint. 
Fibers  tough 

Yel.,  wh.,  grnh., 
redh. 

Resinous 

2  -3 

2.0-2.2 

4-5 

Amorph. 

F.  uneven,  conch. 
Much  cracked 

Wh.  to 
gryh-wh. 

Dull 

2  -2* 

1.0-2.0 

5-5* 

Compact; 
earthy 

F.  uneven,  conch. 

Cols.,  wh. 
yelh.,  redh. 

Vitreous 

5  -5| 

2.2-2.3 

2* 

Iso.;  us.  xls., 
Trapazoh., 
Fig.  3 

F.  uneven,  conch. 

Wh.,  gry., 
yel.,  red,  brn. 

Vitreous 

4* 

2.4-2.5 

31 

Mon.;  us. 
twinned  or 
radiated  tufts 

C.  2.  pinac.,  90° 
F.  uneven 

Wh.,  redh. 

Vitreous 

4-4| 

2.2 

3 

Mon.;  twinned, 
or  radiated 
tufts 

C.  2,  pinac.,  90° 
F.  uneven 

234       SECTION  20.— Concluded.     Nonmetallic  luster;  f us.  1-5;  no  metal  on  ch.;  not  mag. 


Name. 

Composition. 

Fus.  quietly 

To  wh.  enamel;   Na  flame;  little 
H2O.     Gmelinite   often   cracks 
and  splits  b.b. 

PECTOLITE 
(See  p.  52) 

HNaCa2(SiO3)3 

Gmelinite 

(Na2,Ca)Al2(SiO3)4- 
6H2O 

Fus.  with  intumes. 

To    b  1  e  b  b  y 
white  enamel 

K  flame 

APOPHYLLITE 

(See  p.  33) 

(H,K)2Ca(SiO3)2-H2O 

(A  little  F) 

Slowly  and  diff. 
sol.  in  HC1; 
little  H2O 

PREHNITE 
(See  p.  125) 

H2Ca2Al2(SiO4)3 
(Fe  Iso.  w.  Al) 

Gives  slimy  sil. 
inHCl 

CHABAZITE 
(See  p.  42) 

CaAlo(SiO3)4-6H2O 
(Somet.  K,  Na,  Ba,  Sr) 

To      white 
enamel 

Exfoliates  b.b. 

STILBITE 
(Desmlne) 
(See  p.  32) 

H4(Ca,Na2)Al2 
(SiO3)6-4H2O 

Pearly  cl.  faces 
lozenge-shaped 

HEULANDITE 
(See  p.  32) 

H4(Ca,Na2)Al2 
(SiO3)6-3H2O 

SECTION  21.     Nonmetallic  luster;  f  us.  1-5;  no  metal  on  ch.;  not  mag.  after  r.f. ;  not  alk. 


Yel.  WO3  res.  on  boiling 
inHCl 

Strong  Mn  reac.  in  borax 
bead 

HUEBNERITE 

(See  p.  21) 

MnWO4 

(Fe  Iso.  w.  Mn) 

Ca  w.  am.  oxalate;  cupro- 
scheelite,  Cu  flame 

SCHEELITE 
(Cuproscheellte) 
(See  p.  89) 

CaWO4 

(Us.  also  Mo;  somet.  Cu) 

Fus.  quietly  to  glassy 
globule;  slowly  sol.  in 
HC1 

Us.  striated  on  best  cl.  ;  often 
brilliant  play  of  color 

LABRADORITE 
(Ca-Na  Feldspar) 
(See  p.  37) 

n(NaAlSisO8) 
m(CaA!2Si2O8) 
(»:m=l:  1  to  1:3) 

Fus.  dif.  to  wh.  globule; 
rather  easily  sol.  in 
HC1 

HC1  sol.  gives  no  Al  ppt.  w. 
am.;  but  Ca  reac.  w.  am. 
oxalate 

WOLLASTONITE 

(See  p.  35) 

CaSiO3 

(Somet.  H,  Mg) 

Ti  reac.  w.  H2O2 

Fus.  w.  intumes.  to  dk.  glass 

TITANITE 

(Sphene) 
(See  p.  82) 

CaSiTiOs 
(Some  Fe;  somet.  Mn) 

Fus.  w.  intumes.  to 
white  mass 

Cl  reac.  w.  AgNOi;  slowly 
sol.  in  acids;  Na  flame 

WERNERITE 
(Seapollte) 
(See  p.  44) 

n(Ca4Al6Si,;O26) 
m(Na4Al3Si9O24Cl) 
n  :  m  =  3  :  1  to  1  :  2) 

after  r.f.;  not  alk.  after  ign.;  decomposed  by  HC1  w.  separation  of  sil.;  water  in  c.t. 


235 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Cols.,  wh., 
gry. 

Vitr,  silky. 
C.  pearly 

4|-5 

2.7-2.8 

2| 

Mon.;  fibr., 
radiated, 
comp. 

C.  2,  pinac.,  per., 
85°,  95° 
F.  splint.,  uneven 

Wh.,  yel., 
flesh-red,  grnh. 

Vitreous 

4* 

2  0-2.2 

2* 

Hex.  rhom.; 
us.  xls. 

C.3,prism.60°,120° 
F.  uneven 

Wh.,  grnh., 
yelh.,  redh. 

Vitreous; 
C.  pearly 

4J-5 

2.3-2.4 

11 

Tetr.;  us. 
cube-like  xls. 

C.  1,  basal,  per. 
F.  uneven 

Apple-grn., 
gry.,  wh. 

Vitreous 

6  -6£ 

2.8-3.0 

2 

Orth.;  us. 
globular; 
tabular  xls. 

C.  1,  basal,  poor 
F.  uneven 

Wh.,  yel., 
flesh-red 

Vitreous 

4J-5 

2.0-2.2 

3 

Hex.  rhom.  ; 
xls.  nearly 
cubic 

C.  3,  rhom.,  85° 

F.  uneven 

Wh.,  yel., 
brn.,  red 

Vitreous; 
C.  pearly 

3|-4 

2.1-2.2 

2-2* 

Mon.;  twinned; 
sheaf-like 
radiated 

C.  1,  pinac.  per. 
F.  uneven 

Wh.,  yel.,  gry., 
red,  brn. 

Vitreous; 
C.  pearly 

3i-4 

2.2 

2-2  § 

Mon.;  tabular 
xls.  look  orth. 

C.  1,  pinac.  per. 
F.  uneven 

after  ign.;  decomposed  by  HC1  w.  separation  of  sil.  or  yel.  WO3  res.;  little  or  no  water  in  c.t. 


Brn.  to  brnh- 
blk. 

Resinous 

5  -5.5 

6.9-7.4 

4 

Mon.,  us.  xls. 

C.  1,  pinac.  per. 
F.  uneven 

Wh.,  yel., 
grn.,  brn., 
redh. 

Vitreous  to 
adamant 

4.5-5 

5.9-6.1 

5 

Tetr.;  gran.; 
xls.  like  octa- 
hedrons. 

C.  4,  pyram.,  49  J°, 
80° 
F.  uneven,  conch. 

Wh.,  gry., 
brn.,  grn. 

Vitreous  to 
pearly 

5  -6 

2.7 

3-4 

Tri.  ;  us.  mass. 

C.  2.  basal,  per. 
and  pinac.,  86° 
F.  uneven 

Cols.,  wh., 
gry.,  yel., 
red,  brn. 

Vitreous; 
C.  pearly 

4|-5 

2.8-2.9 

4 

Mon.;  us.  gran., 
fibr.,  comp. 

C.  2,  pinac.,  per., 
84*° 
F.  uneven 

Cry.,  brn., 
yel.,  grn. 

Res.  to 
adamant 

5  -5| 

3.4-3.6 

3 

Mon.;  tabular 
wedge-shaped 
xls. 

C.  2,  prism.,66i° 
F.  conch. 
P.  4,  pyram. 

Wh.,  gry., 
grnh.,  bluish, 
redh. 

Vitreous  to 
pearly 

5  -6 

2.6-2.8 

3 

Tetr.;  comp., 
gran.,  stout 
prisms 

C.  3,  prism,  and 
pinac.,  poor 
F.  uneven,  conch. 

236 


SECTION  22.     Nonmetallic  luster;  fus.  1-5;  no  metal  on  ch.;  not  mag. 


Name. 

Composition. 

Li  flame;    thin    flakes 
elastic 

Easily  fus.  to  wh.  or  gry. 
globule;  acid  H2O  in  c.t. 
on  intense  ign. 

LEPIDOLITE 
(Llthla  Mica) 
(See  p.  31) 

(Li,K)2Al2(OH,F)2 
(SiO3)3 

Exfoliates  greatly;  fus.  w. 
dif.;  much  H2O  in  c.t. 

Cookeite 

LiAl(F,OH)2(SiO3)2 

Decomposed  by  boiling 
cone.  H2SO4.  (Flakes 
lose  luster  and  transp. 
and  acid  becomes  tur- 
bid) ;  thin  flakes  elas- 
tic, except  chlorite 
and  kammererite 

Us.  dk.  col.;  often  w.  quartz 
and  feldspar  and  in  igneous 
rocks 

BIOTITE 

(Black  Mica) 
(See  p.  58) 

(K,H)2(Mg,Fe)2 
Al2(Si04)3 
(A  little  F,  often  Ti) 

Gel.  silica  w.HCl 

Lepidomelane 

(K,H)2Fe3(Fe,Al)4 
(Si04)6 

Lt.  to  dk.  col.;  much  more 
readily  decomposed  than 
biotite 

PHLOGOPITE 

(Magnesia  Mica) 
(See  p.  106) 

H2KMg3Al(Si04)3 
(Some  F,  Fe) 

Thin  flakes  flex,  but  not 
elastic;  much  H2O 

CHLORITE 

(Cllnochlore,  etc.) 
(See  p.  104) 

H,Fe,Mg,Al  silicates 

Rose-red;  Cr  in  borax  bd.; 
thin  flakes  flex,  but  not 
elastic 

Kammererite 
(Chrome  Chlorite) 
(See  p.  75) 

Hs(Mg,Fe)s(Al,Cr)j 

Si30l3 

Not  decomposed  by  boil- 
ing cone.  H2SO4. 
(Flakes    retain    luster 
and  transp.,  acid  re- 
mans clear) 

Common  It.  colored  mica; 
elastic;  us.  w.  quartz  and 
feldspar 

MUSCOVITE 

(Potash  Mica) 
(See  p.  30) 

H2KAl3(SiO4)3 
(Often  some  Na,  Ca, 
Mg,  Fe,  F) 

Na  flame  ;  thin  flakes  elastic 

Paragonite 
(Soda  Mica) 
(See  p.  31) 

H2NaAl3(SiO4)3 

Soft;  greasy  feel;  thin  flakes 
flex,  but  not  elastic;  sectile 

TALC 

(Steatite,  Soapstone) 
(See  p.  29) 

H2Mg3(Si03)4 

Thin  flakes  brittle;  harder 
than  true  micas 

MABGABITB 
(Brittle  Mica) 
(See  p.  32) 

H2CaAl4Si2Oi2 
(Some  Fe,  Na,  K) 

Fus.  easily  to  blk  glass;  V 
in  a.  ph.  bead 

ROSCOELITE 
(Vanadium  Mica) 
(See  p.  105) 

H2K(Al,V)3(Si04)3 
(Some  Mg.  Fe) 

after  r.f.;  not  alk.  after  ign.;  insol.  in  HCI;  micaceous,  foliated,  or  scaly 


237 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Lilac.,  gryh-wh., 
redh.,  yelh. 

Pearly 

2  -3 

2.8-2.9 

2-2  1 

Mon.  ;  us.  scaly, 
comp. 

C.  1,  basal,  per. 
Flakes  tough, 
elastic 

Wh.  to  yelh- 
grn. 

Pearly 

2* 

2.7 

4*-5 

Mon.  ;  us.  scaly 

C.  1,  basal,  per. 
Flakes  elastic 

Grn.,  yel., 
brn.,  blk. 

Splendent  to 
pearly  and 
submet. 

2'  -3 

2.7-3.1 

5 

Mon.;  6-sided 
plates,  scaly 

C.  1,  basal,  per. 
Flakes  tough, 
elastic 

Blk.  to 
grnh-blk. 

Adamant,  to 
pearly 

3 

3-3.2 

4>-5 

Mon. 

C.  1.  basal,  per. 
Flakes  tough 

Yelh-brn., 
grn.,  wh., 
cols. 

Pearly  to 
submet. 

2  -3 

2.8-2.9 

4^-5 

Mon.;  6-sided 
xls.,  plates, 
scales 

C.  1,  basal,  per. 
Flakes  tough, 
elastic 

Grn.  of  various 
shades 

Vitreous  to 
pearly 

1  -2* 

2.6-3.0 

5-5J 

Mon.;   scaly, 
foliated 

C.  1,  basal,  per. 

Rose-red  to 
deep  red 

Vitreous  to 
pearly 

1  -21 

2.6-3.1 

5-5  } 

Mon.;  scaly, 
foliated 

C.  1,  basal  per. 
Flakes  tough, 
flex. 

Wh.,  gryh., 

yelh.,  grnh., 
brnh. 

Vitreous  to 
pearly 

2  -3 

2.7-3.0 

4^-5 

Mon.;  foliated, 
flaky,  scaly 

C.  1,  basal,  per. 
Flakes  tough, 
elastic 

Yelh.,  grnh., 
gryh-wh. 

Pearly  to 
vitreous 

2  -3 

2.8-2.9 

5 

Mon.;  us. 
scaly,  comp. 

C.  1,  basal,  per. 
Flakes  tough, 
elastic 

Apple-grn., 
gry.,  wh. 

Greasy  : 
C.  pearly 

1-2.5 

(Somet. 
3  -4) 

2.5-2.8 

5 

Mon.;  us. 
foliated,  gran., 
comp. 

C.  1,  basal,  per. 
Sectile 
Flakes  flex. 
F.  uneven 

Pink,  gry., 
wh.,  yelh. 

Vitreous; 
C.  pearly 

31-41 

3.0-3.1 

±4\ 

Mon.,  scaly, 
micaceous 

C.  1,  basal,  per. 
Flakes  brittle 

Dk.  grn.  to  brn. 

Pearly 

2 

2.9-3.0 

2* 

Mon.(?) 
minute  scales 

C.  1,  basal,  per. 

•      ' 

238 


SECTION  23.     Nonmetallic  luster;  fus.  1-5;  no  metal  on  cli.;  not  mag. 


Name. 

Composition. 

FELDSPAR 
Group.  — 
G.  2.5-2.8. 
2  cl.  at  90° 
or     nearly 
so;    It.  col. 
Fus.  quiet- 
ly; H.  near 
6 

K  flame,  w. 
gypsum 

Microcline  may  show 
striations  on  cl.  or  xl. 
faces  ;  adularia  transp. 
or  opalescent;  sani- 
dine  glassy 

ORTHOCLASE 

(Potash  Feldspar; 
adularia;  sanldlne) 
(See  p.  37) 

KAlSisOs 
(Na  Iso.  w.  K) 
(Sanldlne  contains 
Na) 

MICROCLINE 
(See  p.  37) 

KAlSiaOs 
(Na  Iso.  w.  K) 

Strong  Na 
flame  w.  gyp- 
sum; little  or 
noK 

Us.   fine    striations    on 
best  cleavage;     these 
Plagioclase     Feldspars 
form      a      continuous 
series  from  albite  to  an- 
orthite.      Labradorite 
and  bytownite  slightly 
sol  in  HC1;   anorthite 
slowly  sol.  giving  gel. 
sil.     Distinguished  by 
sp.gr. 

ALBITE 

(Soda  Feldspar) 
(See  p.  37) 

NaAlSisOs 
(Us.  some  Ca; 
often  K) 

OLIGOCLASE 

(Na-Ca  Feldspar) 
(See  p.  37) 

m(NaA18i3O8) 
n(CaAl2Si208) 
(ro:n  =  6:l  to  3:  1) 

ANDESINE 

(Na-Ca  Feldspar) 
(See  p.  37) 

m(NaAlSi3O8) 
n(CaA!2Si2O8) 
(m:n  =  3:  1  to  1:  1) 

LABRADORITE 

(Ca-Na  Feldspar) 
(See  p.  37) 

w(NaAlSi3Os) 
n(CaAl2Si2O8) 
m:n=l:  1  tol:3 

BYTOWNITE 
(Ca-Na  Feldspar) 
(See  p.  37) 

m(NaAlSi3O8) 
n(CaAl2Si2O8) 
(m:  n-  1:  3  to  1:  6) 

ANORTHITE 
(Lime  Feldspar) 
(See  p.  37) 

CaAljSiiOs 
(Us.  some  Na) 

AMPHIBOLE 
Group.—  G.  2.9-3.4. 
Prism  and  cl.  angles 
56°  and  124°.     Xls. 
us  prismatic,   often 
divergent  or  radial- 
columnar.    Separate 
xls.  us.  6-sided,  ver- 
tically striated,  and 
terminated     by     2 
planes.     Fus.  quiet- 
ly  or   w.    little   in- 
tumes. 

Fus.  to  dark  shiny  globule;  us. 
intumes.  slightly  and  gives 
Na  flame 

HORNBLENDE 

(See  p.  61) 

Ca(Mg,Fe)3(Si03)4 
(Also  Ai,  Na:  often 
H,  F) 

Fus.  to  grnh.  or  brnh.  globule; 
but  little  Na  flame;  some- 
times asbestiform  (fibrous) 

ACTINOLITE 

(Nephrite  or  Jade 
In  part) 

(See  p.  110) 

Ca(Mg,Fe)3(SiO3)4 

Fus.  to  cols,  or  nearly  cols, 
glass;  sometimes  asbestiform 
(fibrous) 

TREMOLITE 

(Asbestos  In  part; 
(Nephrite  or  Jade 
In  part) 

(See  p.  36) 

CaMg3(SiO3)4 
(Somet.  Fe) 

Dif  .  fus.  (5-6)  ;  sometimes  as- 
bestiform (fibrous) 

Anthophyllite 
(Asbestos  In  part) 
(See  p.  62) 

(Mg,Fe)SiO3 
(Somet.  also  Al) 

Strong  Na  flame  ;  fus.  easily 

Glaucophane 
(See  p.  112) 

Na(Mg,Ca,Fe)Al 
(Si03)j 

after  r.f.;  not  alk.  after  ign.;  insol.  in  HC1;  distinct  cleav.,  2  directions 


239 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Cols.,  wh., 
cream,  flesh- 
red,  gry., 

6 

2.57 

5 

Mon.  ; 
Figs.  24^4 

C.  2,  basal,  per. 
and  pinac.  90° 

grn. 

6-63 

2.54-2.57 

5 

Tri. 

C.  2,  basal,  per. 
and  pinac.  89°  30' 

6-6J 

2.62-2.64 

4-4! 

Tri.;  Fig.  46 

C.  2,  basal,  per. 
and  pinac. 
86°  24' 

Cols    wh 

Vitreous 

6-6i 

2.65-2.67 

3M 

Tri.;  us.  comp. 

C.  2,  basal,  per. 
and  pinac. 
86°  32' 

gry.,  grnh., 
bluish,  redh. 
Often  a  beau- 

to  pearly 

5-6 

2.68-2.69 

3|-4 

Tri.;  us.  comp. 

C.  2,  basal,  per. 
and  pinac. 
86°  14' 

colors  on 
(010),    most 
notable      in 

5-6 

2.70-2.72 

3  -8i 

Tri.;  us.  comp. 

C.  2,  basal,  per. 
and  pinac. 

86°  4' 

5-6 

2.73-2.75 

3* 

Tri.;  us.  comp. 

C.  2,  basal,  per. 
and  pinac. 
85°  58' 

6-6| 

2  .  75-2  .  76 

4£-5 

Tri. 

C.  2,  basal,  per. 
and  pinac. 
85°  50' 

Grn.  to  blk. 

Vitreous 
to  pearly 

5-6 

2.9-3.4 

3-4 

Mon.;  us. 
prism,  xls.; 
gran. 

C.  2,  prism,  per., 
56° 
F.  uneven,  splint. 

Grn.  of  various 
shades 

Vitreous 
to  pearly 

5-6 

3.0-3.2 

4 

Mon.;  slender 
prism., 
radiating 

C.  2,  prism,  per., 
56° 
F.  uneven,  splint 
Fibers  flex. 

Wh.,  gry. 

Vitreous 
to  pearly 

5-6 

2.9-3.1 

4 

Mon.,  bladed, 
fibr.,  comp. 

C.  2,  prism,  per., 
56° 
F.  uneven 
Fibers  flex. 

Gry.,  clove-brn., 
grn. 

Vitreous 
to  pearly 

5-6 

3.1-3.2 

5-6 

Orth.;  us.  fibr. 
or  lamellar 

C.  2,  prism,  per., 
54|° 
F.  splint. 
Fibers  flex. 

Lavender-blue 
to  azure-blue; 
gryh.,       and 
bluish-blk. 

Vitreous 
to  pearly 

6-6| 

3.0-3.1 

3-3* 

Mon.;  us. 
columnar  or 
fibr. 

C.  2,  prism,  per., 
58° 
F.  uneven,  conch. 
Fibers  flex. 

240 


SECTION  23.— Concluded.     Nonmetallic  luster;  fus.  1-5;  no  metal  on  ch.; 


Name. 

Composition. 

PYROXENE  Group. 
—  G.  3.0-3.7.  Prism 
and     cleav.    angles 
87°  and  93°;    cleav. 
not     very     pro- 
nounced.    Xls.    us. 
nearly  square  prism 
w.  truncated  edges 
4-  or  8-sided.    Basal 
parting    often    dis- 
tinct.    Fus.  quietly 
or  w.  little  intumes. 

Dif.  fus.  (6)  ;  luster  often  me- 
talloidal  (Cp.  hypersthene) 

ENSTATITB 
(Bronzlte) 
(See  p.  36) 

(Mg,Fe)SiO3 

(FeO  up  to  12%) 

Fus.  to  cols,  or  nearly  cols, 
glass 

DIOPSIDE 

(See  p.  36) 

CaMg(SiO3)2 
(Fe  Iso.  w.  Mg) 

Fus.  to  grnh.  or  brnh.  glass; 
col.  deepens  w.  increase  of  Fe. 
Diallage  is  lamellar  to  fibrous 
w.  pearly  to  metalloidal  luster 

PYROXENE 

(Diallage) 
(See  p.  Ill) 

Ca(Mg,Fe)(SiO3)2 

Hedenbergite 
(See  p.  Ill) 

CaFe(SiO3)2 
(Mg  Iso.  w.  Fe) 

Fus.  to  shiny  blk.  glass;  often 
Na  flame;  contains  Al  and 
ferric  Fe 

AUGITE 
(See  p.  62) 

Ca(Mg,Fe)(SiO3)2 
(Also  Al,  somet.  Mn, 
Na) 

Fus.  to  blk.  globule,  somewhat 
mag.  ;  strong  Na  flame 

Aegirite 
(Acmlte) 
(See  p.  63) 

NaFe'"(SiO3)2 

Fus.  readily  to  transp.  blebby 
glass;  Na  flame.  Us.  in  very 
tough  compact  mass 

JADEITE 
(Jade  In  part) 
(See  p.  54) 

NaAl(SiO3)2 

Swells  and  fus.  to  clear  or  wh. 
glass;  Li  flame  (may  be  ob- 
scured by  Na) 

SPODUMENE 
(Hldenlte:  Kunzlte) 
(See  p.  38) 

LiAl(Si03)2 
(Some  Na) 

Mn  in  soda  bead;  fus.  to  nearly 
blk.  glass 

RHODONITE 

(See  p.  83) 

MnSiO3 
(Some  Fe,  Ca) 

Mn  in  soda;  Zn  w.  soda  on  Pt. 
wire.  (See  p.  189) 

Fowlerite 
(See  p.  83) 

Zn-rhodonite 

Jeffersonite 

Zn-Mn-Pyroxene 

SECTION  24.     Nonmetallic  luster;  fus.  1-5;  no  metal  on  ch;  not 


Gel.  w.HCl  after  fus.;  iso.xls.;  red  color 

SPESSABTITE 
(Mn  Garnet) 
(See  p.  102) 

Mn8Al2(SiO4)3 
(Us.  also  Fe  and  Ca) 

Do  not  gel.  after  fus.; 
2  cl.  nearly  90° 

Fus.  to  nearly  blk.  glass 

RHODONITE 
(See  p.  83) 

MnSiO3 
(Fe,  Ca  Iso.  -w.  Mn) 

(Mn,Zn)SiO3 
(Fe,  Ca,Mg  Iso.  w.  Mn) 

Wh.  ZnO  subl.  w.  soda  on  Pt. 
wire  (slight);    grn.  w. 
Co(N03)2 

Fowlerite 
(Zn  Rhodonite) 
(See  p.  83) 

Jeffersonite 
(Mn-Zn  Pyroxene)  • 

(Ca,Mn)(Mg,Fe,Zn) 
(SiO.,)2 

not  mag.  after  r.f.;   not  alk.  after  ign.;  insol.  in  HC1;  distinct  cleav.,  2  directions 


241 


Color. 

Luster. 

Hard- 
ness. 

Specific. 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Yelh.,  gry., 
brn.,  grn. 

Pearly  to 
bronzy 

5  -6 

3.1-3.3 

5-6 

Orth.;  us. 
lamellar 

C.  2,  prism.,  88°, 
poor 
F.  uneven 

Cols.,  wh., 
pale  grn. 

Vitreous 

5  -6 

3.2-3.6 

4 

Mon.;  us.  xls., 
Figs.  40,  41 

C.  2,  prism,  87°, 
poor 
F.  uneven 

Lt.  to  dk.  grn. 

Vitreous 

5  -6 

3.2-3.6 

4 

Mon.;  us.  xls., 
Figs.  40,  41 

C.  2,  prism,  87°, 
poor 
F.  uneven 

Grnh-blk.  to 
blk. 

Vitreous 

5  -6 

3.5-3.6 

21-3 

Mon. 

C.2,prism,87°,poor 
F.  uneven 

Grnh-blk  to 
blk. 

Vitreous 

5  -6 

3.2-3.6 

3-4 

Mon.,  gran., 
columnar 

C.  2,  prism,  87°, 
poor 
F.  uneven 

Grnh.  to 
brnh-blk. 

Vitreous 

6  -6* 

3.5-3.6 

31 

Mon.;  prism. 

C.  2,  prism.,  87°, 
poor 
F.  uneven 

Wh.,  gryh., 
grnh. 

Vitreous 
C.  pearly 

51-61 

3.0-3.3 

2.5 

Mon.;  comp. 

F.  splint.,  tough 

Wh.,  gry., 
pink,  emerald- 
grn.,  purple 

Vitreous 
pearly 

6  -7 

3.1-3.2 

31 

Mon.  ;  cleavable, 
comp. 

C.2,prism,per.,87° 
F.  uneven,  splint. 

Rose-red, 
pink,  brn. 

Vitreous 

5}-6J 

3.4-3.7 

21-3 

Tri.;  us.  gran., 
comp. 

C.  2,  prism.,  per., 
871° 
F.  uneven,  conch. 

(See  below) 

(See  below) 

mag.  after  r.f.;  not  alk.  after  ign.;  insol.  in  HC1;   Mn  reac.  in  soda  bead 


Brnh-red  to 
hyacinth-red 

Vitreous 

61-71 

4.0-4.3 

3 

Iso.;  us.  xls. 

F.  uneven,  conch. 

Rose-red 
pink,  brn. 

Vitreous 

5|-61 

3.4-3.7 

21-3 

Tri.;  us.  gran., 
comp. 

C.  2,  prism,  per., 
871° 
F.  uneven,  conch. 

Rose-red 

Vitreous 

51-61 

3.7 

21-3 

Tri.;  gran., 
comp. 

C.  2,  prism,  per., 
871° 
F.  uneven,  conch. 

Grnh-blk  to 
brn. 

Vitreous 

5  -6 

3.4-3.6 

3-31 

Mon.;  xls., 
gran.,  comp. 

C.  2,  prism.,  87° 
F.  uneven 

242 


SECTION  24.— Concluded.     Nonmetallic  luster;  fus.  1-5;  no  metal  on  ch; 


1 

Name. 

Composition. 

Fus.  w.  much  intumes.  to  blk.  glass 

Piedmontite 
(Mn  Epldote) 

Ca2(Al,Mn,Fe)3 
(OH)(SiO4)j 

Cb.  reac.  after  fus.  w.  borax;  samarskite  gives  U  reac. 
in  s.ph.  bd. 

COLUMBITE 

(See  p.  134) 

(Fe,Mn)Cb2Oe 
(Also  Ta,  and  some  Sn 
and  W) 

Samarskite 
(See  p.  133) 

(Fe,Ca,U02)3 
(Ce,Y,Er)2 
(Cb,Ta)6O2i 

W  reac.  after  fus.  w. 
soda 

W.  little  soda  on  ch.  becomes 
mag. 

WOLFRAMITE 

(See  p.  21) 

(Fe,Mn)WO4 

Little  or  no  Fe 

HUEBNERITE 

(See  p.  21) 

MnWOi 
(Some  Fe) 

SECTION  25.     Nonmetallic  luster;  fus.  1-5;  no  metal  on  ch.;  not 


Li  flame;  may  be- 
yelh-red  or  obscured 
by  Na 

Swells  and  fus.  to  clear  or  wh. 
glass.  Hiddenite  (emerald- 
green)  and  kunzite  (lilac)  are 
transp. 

SPODUMENE 
(Hlddenlt*: 
Kunzite) 
(See  p.  38) 

LiAl(Si03)2 
(Na  Iso.  w.  LI) 

Blue  phosphorescence  with 
gentle  heat.  Fus.  to  wh. 
enamel 

Petalite 

LiAl(Si206)2 
(Na  iso.  w.  LI) 

P  reac.  after  fus.  w.  soda 
Fus.  easily  w.  intumes.  to  wh. 
globule 

AMBLTGONITE 
(See  p.  37) 

Li(AlF)PO4 
(Nalso.'w.LI;  OHw.F) 

B  flame  (Cp.  axinite, 
below) 

Rdh.  phosphorescence  on  heat- 
ing; fus.  to  cols,  glass 

DANBURITE 
(See  p.  102) 

CaB2(Si04)2 

Fus.  w.  intumes.  to  wh.  glob- 
ule ;  Cl  reac.  w.  CuO  on  ch. 

BORACITE 

(See  p:  56) 

Mg7Cl2B1603o 

B  flame  w.  KHSO4 
and  fluorite 

Fus.  w.  intumes.  and  pale  B 
flame 

AXINITE 
(See  p.  80) 

HCasAl2B  (SiO«)4 
(Mn,  Fe.  Mg  Iso.  w.  Ca) 

Fus.  w.  intumes.  to  blebby 
glass  or  slag.  Pyroelectric, 
especially  lighter  colored  va- 
rieties. Achroite  cols.;  indi- 
coliteblue;  ru  belli  te  red 

TOURMALINE 
(Schorl:  Achroite;  Indl- 
ollte;  Rubelllte) 
(See  p.  74) 

RsAl3(BOH)2(SiO6)4 
(R  =  Mg.Fe.Ca,Na,K. 
LI;  often  some  F^ 

not  mag.  after  r.f.;  not  alk.  after  ign.;  insol.  in  HC1;   Mn  reac.  in  soda  bead. 


243 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Redh-brn  to 
redh-blk. 

Vitreous 

6* 

3.4 

3 

Mon.;  comp. 

C.  1,  basal,  per. 
F.  uneven 

Fe-blk.  to  gry. 
and  brnh-blk. 

Res.  to 

submet. 

6 

5.3-6.5 

5-5  } 

Orth.;  short 
prism,  xls. 

C.  1,  pinac.,  poor 
F.  uneven,  conch. 

Velvet-blk. 

Vitreous 
to  res. 

5  -6 

5  .6-5.8 

4§-5 

Orth.  ;  us.  mass. 

F.  conch. 

Dk.  gryh-blk. 
to  brnh.  blk. 

Res.  to 
submet. 

5  -5J 

7.2-7.5 

3-3  1 

Mon.;  us.  xls., 
gran. 

C.  1,  pinac.  per. 
F.  uneven 

Brn.  to 

bnh-blk. 

Resinous 

5  -5i 

6.9-7.4 

4 

Mon.  ;  us.  xls. 

C.  1,  pinac.  per. 
F.  uneven 

mag.  after  r.f .;  not  alk.  after  ign. ;  insol.  in  HC1;  not  previously  included 


Wh.,  gry., 
pink,  emerald- 
grn.,  purple 

Vitreous  to 
pearly 

6  -7 

3.1-3.2 

31 

Mon.;  cleavable, 
comp. 

C.  1,  prism,  per., 
87° 
F.  uneven,  splint. 
P.  1,  pinac. 

Wh.,  gry., 
pink,  grnh. 

Vitreous; 
C.  pearly 

6  -6i 

2.4-2.5 

4 

Mon.;  us.  mass. 

C.  1,  basal,  per. 
F.  uneven 

Wh.  to  pale 
grn.,  or  blue 

Vitreous  to 
greasy; 
C.  pearly 

6 

3.0-3.1 

2 

Tri.;  us.  mass. 

C.  1,  basal,  per. 
F.  uneven 

WTh.  to  pale 
yel.,  yelh-brn. 
and  cols. 

Vitreous 

7  -7| 

3.0 

3J 

Orth.;  us.  xls. 
like  topaz 

F.  uneven,  conch. 

Cols.,  wh., 
gry.,  yel.,  grn. 

Vitreous 

7 

2.9-3.0 

2 

Iso.  tetrh.;  us. 
isolated  xls. 

F.  conch.,  uneven 

Clove-brn.,  gry., 
grn.,  yel.,  blk. 

Vitreous 

6  -7 

3.2-3.4 

2-2  ^ 

Tri.  xls.,  Fig.  45 
tabular 

C.  1,  pinac. 
F.  conch. 

Blk.,  bra., 
grn.,  blue, 
red,  pink 
wh. 

Vitreous  to 
resinous 

7  -7| 

3.0-3.2 

3-5 
Us.  .3 

Hex.  rhom. 
hemimor.  ; 
Fig.  58; 
prism.,  curved 
triangular 
cross-section 

F.  conch.,  uneven 

244 


SECTION  25.— Continued.     Nonmetallic  luster;  f us.  1-5;  no  metal  on  ch.; 


Name. 

Composition. 

GARNET  Group.— 
Fus.  quietly  (except 
uvarovite)  and  gel. 
w.  HC1  after  fus. 
Us.  dodecahedrons 
and  trapezohedrons. 
(Figs.  3,  7,  8).  No 
cleavage;  parting 
somet.  distinct  6  di- 
rections, 60°,  90°, 
120°  (110) 

Ca  (grossularite)  or  Mg  (py- 
rope)  ppt.  after  fus.  w.  soda 
and  separating  Si  and  Al 
(See  Silicon  (2),  p.  185) 

GROSSULARITE 
(Ca-Al  Garnet) 
(See  p.  102) 

Ca3Al2(SiO4)3 
(Often  Fe,  Mg,  Mn) 

PYROPE 
(Mg-Al  Garnet) 
(See  p.  101) 

Mg3Al2(Si04)3 
(Often  Fe,  Ca,  Cr) 

Fus.  to  mag.  globule 

ALMANDITE 
(Fe-Al  Garnet) 
(See  p.  101) 

Fe3Al2(SiO4)3 
(Mn,  Mg,  Ca  Iso.  w.  Fe) 

Mn  in  borax  bd.  (strong) 

SPESSARTITE 
(Mn  Garnet) 
(See  p.  102) 

Mn3Al2(SiO4)3 
(Fe,  Ca  Iso.  w.  Mn; 
Fe  Iso.  w.  Al) 

Partially  sol.  in  HC1  w.  gel.  ail. 

ANDRADITE 
(Ca-Fe  Garnet) 
(See  p.  102) 

Ca3Fe2(SiO4)3 
(Fe,  Mn,  Mg  Iso.  w. 
Ca;  Al  Iso.  w.  Fe) 

Cr  in  s.ph.  bd.  ;  fus.  w.  dif. 

Uvarovite 
(Ca-Cr  Garnet) 
(See  p.  102) 

Ca,Cr»(Si04), 
(Al  Iso.  w.  Cr.) 

Fus.  easily  to  wh. 
transl.  glass 

Wh.  ppt.  BaSO4  in  HC1  sol.; 
much  H2O  in  c.t.  at  low 
temp. 

HARMOTOME 
(See  p.  34) 

H2BaAl2(SiO3)6-4H2O 

Fus.  easily  to  cols, 
blebby  glass 

Sol.  w.  gel.  after  ign.  ;  H2O  in 
c.t.;  very  hard 

Lawsonite 
(See  p.  38) 

CaAl2(OH)4(Si03)2 

Fus.  dif.  and  quietly 

Whitens  and  fus.  to  vesic.  sco- 
ria; varieties  with  Na,  Li, 
Cs,  more  fus. 

BERYL 

(Emerald,  deep  green; 
Aquamarine,  pale) 

(See  p.  127) 

Gl3Al2(Si03)6 
(Some  H;  somet.  Na, 
LI,  Cs,  Ca) 

A  little  H2O  on  intense  ign.  of 
powder  in  c.t. 

CORDIEHITE 

(lollte) 
(See  p.  108) 

(Mg,Fe)4Al8(OH)2 
(Si207)s 

Fus.  to  wh.  enamel 
w.  orange-yel. 
phosphoescence 

Acid  H2O  in  c.t.;  P  reac.  w. 
am.  mol.  after  fus.  w.  soda 

Herderite 

Ca[Gl(F,OH)]PO4 

Fus  w.  intumes. 

(Concluded  on  next 
page) 

To  grnh.  or  brnh.  glass;  gel.  w. 
HC1  after  fus. 

VESUVIANITE 
(Idocrase) 
(See  p.  101) 

Ca6Al3(OH,F)(SiO4)6 
(Mg,  Fe.  Mn  Iso.  w.  Ca) 

To  wh.  blebby  glass;  strong 
Na  -flame;  AgCl  ppt.  w. 
AgNO3  in  dil.  HNO3  sol.  after 
fus.  w.  soda 

WERNERITE 
(Scapollte) 
(See  p.  44) 

n(Ca4Al6Si6O26) 
m(Na4Al3Si9O24Cl) 
(n:m  =  3:  1  to  1:2) 

To  wh.  blebby  glass;  gel.  w. 
HC1  after  fus.  H2O  in  c.t. 

PREHNITE 
(See  p.  125) 

H2Ca2Al2(SiO4)3 
(Fe  Iso.  w.  Al) 

not  mag.  after  r.f.;  not  alk.  after  ign.;  insol.  in  HC1;  not  previously  included 


245 


Color. 

Luster. 

Hard- 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Pale  red,  yel., 
grn.,  wh. 

Vitreous 

6|-7| 

3.5-3.6 

3 

Iso.;  us.  xls., 
Figs.  3,  7,  8 

F.  uneven  to 
conch. 

Deep  red  to 
redh-blk., 
rarely  purple 

Vitreous 

61-71 

3.7-3.8 

3M 

Iso.;  us.  xls., 
Figs.  3,  7,  8 

F.  uneven  to 
conch. 

Deep  red  to 
brnh-blk. 

Vitreous 

• 

6^-7  § 

3.9-4.2 

3 

Iso.;  us.  xls., 
Figs.  3,  7,  8 

F.  uneven,  conch. 

Brnh-red  to 
hyacinth-red 

Vitreous 

6J-7J 

4.0-4.3 

3 

Iso.;  us.  xls., 
Figs.  3,  7,  8 

F.  uneven  to 
conch. 

Wine-red, 
grnh.,  yel., 
brn.  to  blk. 

Vitreous  to 
resinous 

6*-7* 

3.8-3  9 

3i 

Iso.;  us.  xls., 
Figs.  3,  7,  8 

F.  uneven  to 
conch. 

Emerald-grn. 

Vitreous 

7* 

3.4-3.5 

6^-6 

Iso.;  us.  xls., 
Figs.  3,  7,  8 

F.  conch. 

Wh.,  gry., 
yel.,  red,  brn. 

Vitreous 

4* 

2.4-2.5 

31 

Mon.;  us. 
twinned, 
radiating 

C.  2,  pinac.,  90° 
F.  uneven 

Pale  blue  to 
gryh-blue 

Vitreous  to 
greasy 

7i-8 

3.1 

3 

Orth.;  us.  xls. 

C.  2,  basal  and 
pinac.,  per.,  90° 

Grn.,  blue, 
yel.,  pink, 
cols. 

Vitreous  to 
resinous 

7J-8 

2.6-2.8 

5-5  £ 

Hex.;  us.  prism, 
xls.,  Fig.  49 

C.  indistinct 
F.  conch  to 
uneven 

Blue  to  violet 
and  cols. 

Vitreous 

7  -7* 

2.6-2.7 

5-5  £ 

Orth.; 
pseudohex. 
xls.,  gran. 

C.  1,  pinac. 
F.  conch.,  uneven 
P.  1,  basal 

Wh.  to  pale 
grn.  or  yel. 

Vitreous 

5 

3.0 

4-5 

Mon. 

F.  uneven 

Grn.,  brn., 
yel. 

Vitreous  to 
resinous 

61 

3.3-3.5 

3 

Tetr. 
Figs.  27,  28; 
gran. 

F.  uneven 

Wh.,  gry., 
grnh.,  bluish, 
redh. 

Vitreous  to 
pearly 

5  -6 

2.6-2.8 

3 

Tetr.;.  stout 
prism.,  comp., 
gran. 

C.  3,  prism,  and 
pinac.,  poor 
F.  uneven,  conch. 

Apple-grn., 
gry.,  wh. 

Vitreous 

6  -6* 

2.8-3.0 

2 

Orth.; 
us.  reniform 

F.  uneven 

246 


SECTION  25. — Concluded.     Nonmetallic  luster;  fus.  1-5;  no  metal  on 


Name. 

Composition. 

Fus.  w.  intumes.  — 
Concluded 

To  a  slag  which 
gel.   w.   HC1; 
a    little    H2O 
on  intense  ign. 
in  c.t. 

Lt.  col.  slag 

ZOISITE 
(See  p.  33) 

Ca2Al3(OH)(SiO4)s 

Brn.    or    blk. 
slag;    us. 
mag. 

EPIDOTE 

(Plstaclte) 
(See  p.  79) 

Ca2(Al,Fe)3(OH) 
(SiO4)3 

Fus.  w.  slight  intumes. 
to  colored  glass 

Ti  reac.  w.  H2O2 

TITANITE 

(Sphene) 
(See  p.  82) 

CaSiTiO6 
(Some  Fe;  somet.  Mn) 

Benitoite 

BaTi(SiO3)8 

Exfoliates  and  fus.  w. 
dif.     Greasy  feel 

Pink    col.    after   ign.  w. 
Co(NO3)2;   us.  gives  H2O  in 
c.t.  on  intense  ign. 

TALC 

(Steatite.  Soapstone) 
(See  p.  29) 

H2Mg3(Si03)4 

SECTION  26.     Nonmetallic  luster; 


CARBO- 
NATES.— 
CO2      efferv. 
in  dil.    HC1. 

(Cp.  also  the 
carbonates 
on   the   next 
page,  partic- 
ularly   r  h  o- 
d  o  c  hrosite 
and   siderite, 
which      may 
contain  some 
Ca  and  give 
alkaline     re- 
action    after 
ignition.) 

(Concluded  on 

next  page) 

Sr  flame;  swells 
and  throws  out 
fine  branches 
on  intense  ign. 

Wh.  ppt.  SrSO4  w. 
dil.  H2SO4  in  dil. 
HC1  sol. 

STRONTIANITE 
(See  p.  34) 

SrC03 
(Somet.  Ca  Iso.  w.  Sr) 

Ba  flame  on  in- 
tense ign. 

Wh.  ppt.  BaSO4  w. 
dil.  H2S04  in  dil. 
HC1  sol. 

Barytocalcite 

CaBa(C03)2 

Ca  flame  w. 
HC1;  dil. 
H2SO4  gives 
w  h  .  p  p  t  . 
CaSO4  i  n 
cone.  HC1  sol. 
but  n  o  t  i  n 
very  dil.  sol., 
showing  pres- 
ence of  Ca 
and  absence 
of  Sr  and  Ba 
(Abundant 
ppt.  w.  am. 
oxalate.  See 
P.  177) 

Lumps  efferv.  freely 
in  cold  dil.  HC1. 
Aragonite  powder 
colored  lavender 
on  boiling  in 
Co(NO3)2  sol.;  de- 
crepitates b.b. 

CALCITE 
(CalcSpar;  Marble 
Limestone;  Chalk.) 
(See  p.  40) 

CaC03 
(Mg,  Fe,  Mn,  Pb  Iso.  w. 
Ca) 

ARAGONITE 

(See  p.  41) 

CaCO3 
(Sr,  Pb  Iso.  w.  Ca) 

Lumps  efferv.  freely 
in  hot  but  not  in 
cold  dil.  HC1;  sol. 
reac.  for  Mg  after 
ppt.  of  Ca 

DOLOMITE 

(Pearl  Spar) 
(See  p.  40) 

CaMg(CO3)2 
(Fe,  Mn  Iso.  w.  Mg) 

Becomes  blk.  and 
slightly  mag.  on 
ign. 

Ankerite 
(Fe  Dolomite) 
(See  p.  40) 

Ca(Mg,Fe)(CO3)2 
(Mn  iso.  w.  Mg) 

Much  H2O  in  c.t.; 
wh.  BaSO4  ppt.  w. 
BaCl2  in  dil.  HC1 
sol. 

Thaumasite 

CaCOs-CaSiOr 
CaSO4-15H2O 

ch.;  not  mag.  after  r.f.;  alk.  after  ign.;  insol.  in  HC1;  not  previously  included.  247 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Fusi- 
bility. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Gryh-wh., 
grn.,  pink, 
yelh-brn. 

Vitreous; 
C.  pearly 

6  -6£ 

3.2-3.4 

3-4 

Orth.; 
columnar, 
bladed 

C.  1,  pinac.  per. 
F.  uneven 

Yelh.  to  blkh- 
grn.,  gry. 

Vitreous 

6  -7 

3.2-3.5 

3-4 

Mon.; 
us.  prism. 

C.  1,  basal,  per. 
F.  uneven 

Gry.,  brn., 
yel.,  grn. 

Resinous  to 
adamant. 

5  -5£ 

3.4-3.6 

3 

Mon.;  us. 
tabular,  wedge- 
shape  xls. 

C.  2,  prism,  66  1° 
F.  uneven 
P.  4,  pyram. 

Sapphire-blue  , 
It.  blue,  cols. 

6  -6£ 

3.6-3.7 

3 

Hex.; 
us.  prism. 

Apple-grn., 
gry.,  wh. 

Greasy; 
C.  pearly 

1  -2| 
(somet. 
3  -4) 

2.5-2.8 

5 

Mon.;  us. 
foliated,  comp., 
gran. 

C.  1,  basal,  per. 
F.  uneven; 
sectile,  thin 
flakes  flex. 

fus.  above  5;  alk.  after  ign. 


Wh.,  gry.,  yel., 
grn. 

Vitreous 

3|-4 

3.7 

Orth.;  us. 
columnar;  xls. 
pseudohex. 

C.  2,  prism.,  63° 
F.  uneven 

Wh.,  gry.,  yel., 
grn. 

Vitreous 

4 

3.6-3.7 

Mon.;  us.  prism. 

C.  2,  prism,  per. 
F.  uneven 

Cols.,  wh., 
and  variously 
tinted 

Vitreous 

3 

2.7 

Hex.  rhom.; 
Figs.  52-57 

C.  3,  rhom.  per., 
75° 
F.  conch.,  seldom 
observable 

Cols.,  wh.,  and 
variously 
tinted 

Vitreous 

31-4 

2.9-3.0 

Orth.;  often 
pseudohex. 

C.  3,  pinac.,  poor 
F.  uneven 

Cols.,  wh.,  and 
variously 
tinted 

Vitreous  to 
pearly 

3|-4 

2.8-2.9 

Hex.  rhom.  ; 
gran.,  comp.  ; 
xl.  faces  curved 

C.  3,  rhom.  per., 

74° 
F.  conch.,  uneven 

Brn.,  gry., 
redh.,  seldom 
wh. 

Vitreous  to 
pearly 

3M 

2.9-3.1 

Hex.  rhom. 

C.3,  rhom.  per.,  74° 

Wh.,  cols. 

Vitreous  to 
dull 

3J 

1.8-1.9 

Hex.;  fibr.  or 
mass. 

F.  splint.,  uneven 

248 


SECTION  36.— Concluded.     Nonmetallic 


Name. 

Composition. 

Carbonates  — 
Concluded 

Contains  Mg  — 
Little    or    no 
ppt.    w.    am. 
oxalate        i  n 
HC1  sol.,  but 
much  w.  Na 
phosphate. 
Alkaline    reac. 
w.      turmeric 
paper  may  be 
weak 

Scarcely  affected  by 
cold  dil.  HC1.    Wh. 
fragments   become 
pale  pink  on  ign.  w. 
Co  (NO  3)2.    Breun- 
nerite gives  much 
Fe(OH)3    ppt.    w. 
am.    after    boiling 
HC1  sol.  w.  a  drop 
of  HNO3,    Hydro- 
magnesite      gives 
much  H2O  in  c.t. 

MAGNESITE 

(See  p.  42) 

MgCO3 
(Somet.  Fe,  Mn) 

Breunnerite 
(Fe  Magneslte: 
Brown  Spar) 

(See  p.  42) 

(Mg,Fe)CO3 
(Mn  Iso.  w.  Mg) 

Hydromagnesite 

Mg2(MgOH)2(CO3)3- 

Sol.  quietly   in 
warm  HC1 

Glows  on  ign.;   becomes  pale  pink  if 
previously  moistened  w.  Co(NO3)2 

BRUCITE 
(See  p.  30) 

Mg(OH)2 
(Fe,  Mn  Iso.  w.  Mg) 

Sulphates.  — 
Acid  H2O  in 
c.t.  and  SO2 
odor   after 
intense  ign. 

Al  reac.  w. 

Co(N03)2 

Readily  sol.  in  H2O 

Kalinite 
(Potash  Alum) 

KA1(SO4)2-12H2O 

Slowly  attacked  byHCl; 
decrepitates  b.b. 

ALUNITE 
(See  p.  52) 

KA13(OH)6(S04)2 
(Na  Iso.  w.  K) 

SECTION  27.     Nonmetallic  luster;  fus.  above  5;  not 


CARBO- 
NATES.— 
CO2     efferv. 
in  dil.  HC1. 

Mn  in  borax 
bd.;  decrep- 
itates b.b. 

Sometimes  enough 
Fe  to  make  mag. 
on  ch. 

RHODOCHROSITE 
(Dlaloglte) 
(See  p.  88) 

MnCO3 
(Ca,  Fe,  Mg,  Zn  Iso.  w. 
Mn) 

Ni  in  borax  bd. 

H2O  in  c.t. 

Zaratite 
(See  p.  147) 

Ni3(OH)4CO3-4H2O 

Wh.  ZnO  subl. 
w.  soda  on  Pt 
wire;         grn. 
subl.        w. 
Co(N03)2 
(See  p.  189) 

Little  or  no  H2O  in 
c.t. 

SMITHSONITE 

(Dry-bone  Ore) 
(See  p.  43) 

ZnCO3 

(Often  Fe,  Mn;  somet. 
Ca,  Mg) 

H2O  in  c.t.  ;Cu  flame 
w.  HC1 

Aurichalcite 

(Zn,Cu)5(OH)6CO3)2 

H2O  in  c.t.;   no  Cu 

Hydrozincite 
(See  p.  49) 

Zn3(OH)4CO3 

Becomes  blk. 
and  mag.  on 
ign.;  much 
ferrous  Fe 

HC1  sol.  reac.  for 
both  Mg  and  Fe. 
(See  breunnerite, 
Sec.  26,  above) 

Breunnerite 
(Fe  Magneslte) 
(See  p.  42) 

(Mg,Fe)C03 
(Mn  Iso.  w.  Mg) 

Decrep.  inc.  t.  ;  little 
or  no  Mg  or  Ca 

SIDERITE 

(Spathic  Iron) 
(See  p.  41) 

FeC03 
(Ca,  Mg,  Mn  Iso.  w.  Fe) 

Mg  reac.  in 
HC1.  sol.  after 
removing  Fe 
andCa.  (See 
Magnesium 
(3),  p.  182) 

Little  or  no  H2O  in 
c.t. 

MAGNESITE 
(See  p.  42) 

MgCO3 
(Somet.  Fe,  Mn) 

Much  H2O  in  c.t. 

Hydromagnesite 

Mg4(OH).,(C03)3- 
3H2O 

luster;  fus.  above  5;  alk.  after  ign. 


249 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Wh.,  yel.,  gry., 
brn. 

Vitreous, 
silky,  dull 

3  Ml 

3.0-3.1 

Hex.  rhom.  ; 
us.  comp.,  gran. 

C.  3,  rhom.  per.,  72  1° 
F.  conch. 

Yelh.,  brnh., 
gry.     Seldom 
wh. 

Vitreous 

3  Ml 

3.0-3.2 

Hex.  rhom. 

C.  3,  rhom.  per.  72  £° 

Wh. 

Vitreous  to 
silky 

31 

2.1-2.2 

Mon.;  us.  acic. 

Wh.,  gry.,  grn., 
blue 

Waxy,  vitr. 
C.  pearly 

21 

2.3-2.4 

Hex.  rhom.; 
us.  foliated 

C.  1,  basal,  per. 
Sectile;  flakes  flex. 

Cols.,  wh. 

Vitreous 

2  -2| 

1.7-1.8 

Iso.  pyr.; 
us.  fibr. 

C.  conch. 

Wh.,  gry., 
redh. 

Vitreous 

3M 

2.6-2.8 

Hex.  rhom. 

C.  1,  basal,  poor 
F.  uneven 

alk.  after  ign.;  sol.  in  HC1  without  res.  or  gel.  sil. 


Rose-red,  dk. 
red,  brn. 

Vitreous  to 
pearly 

81-41 

3.4-3.6 

Hex.  rhom.; 
gran.,  comp. 

C.  3,  rhom.  per.,  73° 
F.  uneven 

Emerald-grn. 

Vitreous 

3 

2.6-2.7 

Compact, 
incrust. 

F.  smooth 

Brn.,  grn., 
blue,  pink, 
wh. 

Vitreous 

5 

4.3-4.5 

Hex.  rhom.;   us. 
botry.,  incrust., 
cellular 

C.  3,  rhom.  per.,  72° 
F.  uneven,  splint. 

Pale  grn.  to 
blue 

Pearly 

2 

3.5-3.6 

Mon.;  us.  acic., 
gran.,  laminated 

F.  splint. 

Wh.,  gry.,  yel. 

Dull 

2  -2| 

3.6-3.8 

Earthy,  compact, 
fibr. 

F.  uneven,  splint. 

Yelh.  brnh., 
gry.    Seldom 
wh. 

Vitreous 

3M1 

3.0-3.2 

Hex.  rhom. 

C.  3,  rhom.  per.,  72  i° 
F.  conch. 

Gry.  and  brn. 
of  different 
shades 

Vitreous  to 
pearly 

3|-4 

3.8-3.9 

Hex.  rhom.  ; 
gran.,  comp. 

C.  3,  rhom.  per.,  73° 
F.  uneven 

Wh.,  yel.,  gry., 
brn. 

Vitreous, 
silky,  dull 

3Mi 

3.0-3.1 

Hex.  rhom.; 
gran.,  comp. 

C.  3,  rhom.  per.,  72J° 
F.  conch. 

White 

Vitreous  to 
silky    ' 

31 

2.1-2.2 

Mon.;  us.  acic., 
bladed,  chalky 

F.  splint.,  uneven 

250 


SECTION  27. — Continued.     Nonmetallic  luster;  fus. 


Name. 

Composition. 

SULPHIDES. 

—  H2S  efferv. 
inhotHCl 

Wh.  ZnO  subl.  after  intense  ign.  w. 
soda    on    Pt    wire;     subl.    grn    w. 
Co(NO3)2.     (See  p.  189) 

SPHALERITE 

(Zinc  Blende) 
(See  p.  88) 

ZnS 
(Fe,  Mn,  Cd  Iso.  w.  Zn) 

Wurkite 
(See  p.  130) 

ZnS 
(Some  Fe) 

Red-brn.  CdO  subl.  after  intense  ign. 
w.  soda  on  ch. 

GREENOCKITE 
(See  p.  140) 

CdS 

SULPHATES. 
—  Wh.  p  p  t. 
BaSO4  w. 
BaCb  i  n 
HC1  sol. 

Al      reac.      w. 
Co(NO3)2   on 
ch. 

Readily  sol.  in  H2O; 
K  flame 

Kalinite 
(Potash  Alum) 

KA1(SO4)2-12H2O 

Sol.  in  H2O;  no  flame 
react;  alum  taste 

Alunogen 

A12(SO4)3-18H2O 

Readily  sol.  in  H2O;  wh.  ZnO  subl.  w. 
soda  on  Pt  wire  after  intense  ign.; 
taste  astringent,  metallic,  nauseous 

Goslarite 

ZnS04-7H20 
(Fe  lao.  w.  Zn) 

Blackens  and 
becomes 
strongly  mag. 
b.b.;fus.  5-6 
in  fine  splint- 
ers; slowly 
sol.  in  HC1 
to  yel.  sol. 
which  reacts 
for  ferric  Fe 

St.  brnh-red 

Little  or  no  H2O  in 
c.t. 

HEMATITE 
(See  p.  134) 

Fe203 
(Somet.  Tl,  Mg) 

H2O  in  c.t.;  us.  de- 
crepitates 

TURGITE 

(Hydrohematlte) 
(See  p.  144) 

FeO-OH,  Fe2O3,H2O 

St.       yelh-brn. 
H2O  in  c.t. 

Us.    prismatic    xls. 
Lepidocrocite  scaly 

GOETHITE 
CLepldocroclte) 
(See  p.  142) 

FeO-OH 

Amorphous,  mam- 
millary,  botryoid- 
al,  stalactitic 

LIMONITE 
(Brown  Hematite: 
Bog  Iron  Ore) 

(See  p.  131) 

FeO-OH-nH2O 
(Often  clay,  sand,  etc.) 

Mn  in  borax  bd. 

Wh.  ZnO  subl.  w.  soda  on  Pt  wire 
after    intense    ign.;  subl.    grn.    w. 
Co(NO3)2.     (See  p.  189) 

ZINCITE 

(Red  Zinc  Ore) 
(See  p.  141) 

ZnO 

(Mn  Iso.  w.  Zn) 

Earthy,  powdery,  frothy;  H2O  in  c.t. 

WAD 

(Bog  Manganese) 
(See  p.  17) 

MnO,MnO2,H2O 
(Often  Fe,  SI.  Al,  Ba) 

Little  or  no  H2O  in  c.t. 

Hausmannile 
(See  p.  131) 

MnMn2O4 

Co  in  borax  bd. 

Mninsodabd.;  H2Oinc.t. 

Asbolite 
(Earthy  Cobalt) 

Co.Mn  oxides 
(Often  Fe,  SI.  Al) 

P  reac.  w.  am. 
mol. 

(Concluded  on 
next  page) 

Cu  flame 

TURQUOIS 
(See  p.  124) 

A12(OH)3PO4-H2O 

(Some  Cu) 

Wh.   CaSO4  ppt.  w.   H2SO4  in  cold 
cone.  HC1  sol.     F  reac.  w.  H2SO4 

APATITE 
(See  p.  98) 

Ca6F(PO4)3 
(Cl  Iso.  w.  F) 

above  5;  not  alk.  after  ign.;  sol.  in  HC1  without  res.  or  gel.  sil. 


251 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Wh.,  grn.,  yel., 
red,  brn.,  blk. 

Resinous  to 
adamant. 

3M 

3.9-4.1 

Iso.  tetr.;  gran., 
comp. 

C.  6,  dodec.  per.,  60°, 
90°,  120° 
F.  conch. 

Bnh-blk. 

Resinous 

3*-4 

3.9-4.0 

Hex.  hemimor.; 
us.  fibr. 

F.  uneven,  splint. 

Honey-,  citron-, 
or  orange-yel. 

Resinous  to 
adamant. 

3  -3| 

4.9-5.0 

Hex.  hemimor.; 
us.  incrust. 

C.  3,  prism.,  60°,  poor 
F.  conch. 

Cols.,  white 

Vitreous 

2  -2| 

1.7-1.8 

Iso.  pyr.; 
us.  fibr. 

F.  conch. 

Wh.,  yelh., 
redh. 

Vitreous  to 
silky 

ij-a 

1.6-1.8 

Mon.;  us.  fibr., 
incrust. 

F.  splint. 

Wh.,  yelh., 
redh. 

Vitreous 

2  -2| 

1.9-2.1 

Orth.  ;  us.  comp. 

C.  1,  pinac.  per. 

Red  to  redh-blk. 

Dull  to 
submet. 

5I-6J 

4.9-5.3 

Mass.;  earthy 
Hex.  rhom. 

F.  uneven 
splint. 

Red  to  redh-blk. 

Dull  to 
submet. 

5^-6 

4.2-4.7 

Botry.,  crusts, 
stalac.,  earthy 

F.  uneven,  splint, 
earthy 

Yel.  or  redh-brn. 
to  blk. 

Dull  to 
adamant. 

5  -5} 

4.0-4.4 

Orth.;  acic. 
or  scaly 

C.  1,  pinac.  per. 
F.  splint.,  uneven 

Yel.,  brn.  to 
brnh.  blk. 

Dull,  silky 

5  -5$ 

3.6-4.0 

Mass.,  fibr., 
bo  try.,  earthy 

F.  splint.,  uneven 

Deep  red  to 
orange-yel. 
St.  yel. 

Adamant. 

4-4* 

5.4-5.7 

Hex.  hemimor.; 
us.  gran., 
lamellar 

C.  1,  basal,  per. 
F.  uneven 

Bluish  or  brnh- 
blk.  to  dull 
blk. 

Dull 

1  -6 

3.0-4.3 

Earthy,  amorph., 
comp. 

F.  earthy 

Bnh-blk. 
St.  chestnut- 
brn. 

Submetallic 

5  -5} 

4.7-4.9 

Tetr.;  pyr.  xls.; 
gran. 

C.  1,  basal 
F.  uneven 

Blk.,  brn. 

Dull 

1  -2* 

3.1-3.3 

Mass.;  earthy 

F.  uneven,  earthy 

Blue,  bluish- 
grn.,  grn. 

Waxy 

5H5 

2.6-2.8 

Tri.;  incrust., 
comp. 

F.  conch. 

Grn.,  blue, 
violet,  brn., 
yelh.,  cols. 

Vitreous  to 
subres. 

4*-5 

3.1-3.2 

Hex.,  us.  prisms; 
gran. 

C.  1,  basal,  poor 
F.  uneven,  conch. 

252 


SECTION  37.— Concluded.     Nonmetallic  luster;  fus.  above 


Name. 

Composition. 

P  reac. 

—  Concluded. 

Al  reac.  w.  Co(NO3)2  on  ch. 

WAVELLITE 
(See  p.  122) 

(A10H)3(P04)2-5H20 
(Some  F  Iso.  w.  OH) 

Much  Mg;  no 
Ca.  See  Mag- 
nesium (3)  , 
p.  182.  Sec- 
tile 

Brilliant  glow  on  intense  ign.;  Mg 
reac.  w.  Co(NOs)2  on  ch.  if  mineral 
is  light  colored. 

BRUCITE 
(Seep.  30) 

Mg(OH)2 
(Fe.  Mn  too.  w.  Mg) 

SECTION  28.     Nonmetallic  luster;  fus.  above 


Wh.  ZnO  subl. 
w.  soda  on  Pt 
wire.     G  r  n. 
subl.       w. 
Co(N03)2 
(See  p.  189) 

Decrep.  and  gives  H2O  in  c.t.;  pyro- 
electric  ;  almost  inf  us.  (fus.  6) 

CALAMINE 

(Hemlmorphlte; 
Smlthsonlte) 

(See  p.  35) 

(ZnOH)2SiOs 

Little  or  no  H2O  A  little  H2S  on  sol. 
in  c.t.                    in  HC1 

Danalite 

Gl3R4S(Si04)3 
(R  =  Mn.  Fe,  Zn) 

NoH2Sonsol.inHCl 
(Cp.    troostite,    p. 
230) 

WlLLEMITE 

(See  p.  90) 

Zn2Si04 
(Mn,  Fe  Iso.  w.  Zn) 

Cu  globule  w. 
soda  on  ch. 

H2O  in  c.t. 

DlOPTASE 

(See  p.  148) 

H2CuSiO4 

Fe  in  borax  bd.  ; 
little  or  no 
H20  in  c.t. 
(Cp.  next  2 
minerals, 
which  often 
contain  a 
little  Fe) 

Much  Mg  but  no  Al  or  Ca  in  HC1  sol. 
(See  Magnesium  ^3),  p.  182) 

OLIVINE 
(Chrysolite,  Peridot) 
(See  p.  85) 

(Mg,Fe)2SiO4 
(Somet.  a  little  Nl,  Sn, 
Tl) 

Swells  and  cracks  apart  on  ign.  ;  often 
glows;  str.  gnh-gry. 

Gadolinite 
(See  p.  73) 

FeGl2(YO)2(Si04)2 

Little  01  no  Fe 

Much  Mg;  no  Al  nor  Ca 

Forsterite 
(See  p.  85) 

Mg2SiO4 
(Some  Fe) 

F  reac.  w. 
KHSO4;  may 
react  for  Fe 

A  little  H2O  on  intense  ign.  in  c.t. 

CHRONDRODITE 
(See  p.  100) 

Mg6(F,OH)2(SJ04)2 
(Some  Fe) 

Al  reac.  w. 
Co(NO3)2  on 
ch. 

Much  H2O  in  c.t.  ;  crumbles  on  ign. 

ALLOPHANE 
(See  p.  121) 

Al2SiO6-5H2O 

Str.  orange  to 
dk.  brn. 

Brn.  to  brnh-red  on  ign. 

Thorite 
(Orangelte) 
(See  p.  130) 

ThSiO< 
(Some  H2O,  somet.  IT) 

5;  not  alk.  after  ign.;  sol.  in  HC1  without  res.  or  gel.  ail. 


253 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Wh.,  yel.,  grn., 
brn. 

Vitreous  to 
pearly 

3|-4 

2.3-2.4 

Orth.;  us. 
radiating 

C.  3,  pinac.,  73°,  90° 
F.  uneven,  conch. 

Wh.,  gry., 
grn.,  blue 

Waxy, 
vitreous; 
C.  pearly 

2  -2J 

2.3-2.4 

Hex.  rhom.; 
us.  foliated 

C.  1.  basal,  per.  ;  flakes 
and  fibers  flex. 

5;  not  alk.  after  ign.;  sol.  in  HC1  w.  gel.  sil. 


Wh.,  pale-grn., 
blue 

Vitreous 

4^-5 

3.4-3.5 

Orth.  hemimor., 
cockscomb 
groups,  tabular 

C.  2,  prism,  per.,  76° 
F.  uneven,  conch. 

Flesh-red  to 
gry. 

Vitreous  to 
resinous 

5*-6 

3.  4-  -3.  5 

Iso.  tetrh.; 
us.  mass. 

F.  uneven 

Yel.,  red.,  grn., 
brn.,  wh., 
cols. 

Vitreous 

5  -6 

3.9-4.2 

Hex.  rhom.; 
comp.,  gran. 

C.  3,  prism., 
60°,  120° 
F.  uneven,  conch. 

Emerald-grn. 

Vitreous 

5 

3.3-3.4 

Hex.  rhom.; 
us.  prism. 

C.  3,  rhom.  per.,  54° 
F.  conch.,  uneven 

Olive-grn.  to 
gryh-grn., 
brn. 

Vitreous 

6f-7 

3.2-3.6 

Orth;  Fig.  36; 
gran.,  dissem. 

C.  2,  pinac.,  90° 
F.  conch.,  uneven 

Blk.,  grnh-blk.,  , 
brn. 

Vitreous  to 
greasy 

6-7 

4.0-4.5 

Mon.;  comp., 
gran. 

F.  conch.,  splint. 

Wh.,  yelh., 
gryh.,  gnh. 

Vitreous 

6  -7 

3.2-3.3 

Orth.  ;  us.  xls. 

C.  2,  pinac.,  90° 
F.  uneven 

Brnh-red., 
yel.,  wh. 

Vitreous 

6-€| 

3.1-3.2 

Mon.;  comp., 
gran. 

C.  1,  basal 
F.  uneven 

Cois.,  yel., 
grn.,  blue 

Vitreous  to 
waxy 

3 

1.8-1.9 

Amorph.  ; 
us.  crusts 

F.  conch.,  earthy 

Blk.,  brn., 
orange 

Resinous, 
greasy 

4  §-5 

4.4-5.4 

Tetr.  ;  us.  xls. 

C.  2,  prism.,  90° 
F.  conch. 

254 


SECTION  29.     Nonmetallic  luster;  fus.  above  5;  not  alk.  after 


Name. 

Composition. 

Yel.  WO3  powder  in  boil- 
ing HC1 

Ca  reac.  w.  am.  oxalate  in 
HC1  sol. 

SCHEELITE 
(See  p.  89) 

CaWO4 
(Us.  some  Mo,  somet.  Cu) 

Darkens  and  gives  H2O 
in  c.t. 

Cu  globule  w.  soda  on  ch. 

CHRYSOCOLLA 
(See  p.  120) 

CuSiO3-2H2O 

Ni  in  borax  bd. 

GABNIEBITE 
(Genthlte) 
(See  p.  120) 

H2(Ni,Mg)SiO4-«H2O 

H2O  in  c.t.;  amorphous, 
fibrous,  or  foliated 

Us.  compact  grnh.  ;  some- 
times fibrous  (chrysotile, 
commercial  "asbestos")  or 
foliated  (marmolite) 

SERPENTINE 
(Chrysotile; 
Marmolite) 

(See  p.  122) 

(Some  Fe,  somet.  NI) 

Resembles  a  gum  or  resin 

DEWEYLITB 
(Gymnite) 
(See  p.  50) 

H4Mg4(Si04)3-4H20 
(Somet.  NI  Iso.  w.  Mg) 

Compact;  fine  earthy  tex- 
ture; Mgreac.  w.  Co(NO3)2 
on  ch.  Fus.  =  5.  Adheres 
to  tongue 

SEPIOLITE 
(Meerschaum) 
(See  p.  49) 

(Somet.  Cu  and  NI  Iso. 
w.  Mg) 

Al  reac.  w.  Co(NO3)2  on 
ch. 

K  flame  w.  powdered  gyp- 
sum; us.  trapezohedrons 

LEUCITE 

(See  p.  54) 

KAl(SiO3)2 
(Na  Iso.  w.  K) 

Clay-like;  sometimes  transl. 
or  transp.  in  H2O 

Halloysite 
(See  p.  47) 

H4Al2Si2O9-nH2O 

SECTION  30.     Nonmetallic  luster;  fus.  above  5;  not 


Slowly  attacked  by  hot  HC1 
w.  evolution  of  H2S 

Wh.  ZnO  subl.  w.  soda 
on  Pt  wire;  grn.  w. 
Co(NO3)2.  (Seep.  189) 

SPHALERITE 

(Zinc  Blende) 
(See  p.  88) 

ZnS 
(Fe.  Mn.  Cd  Iso.  w.  Zn) 

Wurtzite 
(See  p.  130) 

ZnS 
(Some  Fe) 

Become    strongly    mag.    on 
ign. 

Slowly  and  dif.  sol.  in 
HC1 

IRON  ORES 
(See  Sec.  12,  p.  218) 

Micaceous 
or  foliat- 
ed 

(Concluded 

Flakes  tough  and 
elastic 

Fus.  w.  dif. 

MICA 
(See  Sec.  22,  p.  236) 

Flakes       flexible 
but  not  elastic 
(Cp.    talc,   and 
pyrophyllite, 
next  page) 

on  next  page) 

Much  H2O  in  c.t.  on  in- 
tense ign.  ;  varieties 
rich  in  Fe  become 
black  and  mag.  (pro- 
chlorite) 

CHLORITE 
(Cllnochlore;  Pennine; 
Prochlorlte) 

(See  p.  104) 

H.Fe.Mg.Al  silicates 
(Often  a  little  Cr) 

Cr  in  borax  bd.;  mineral 
pink  to  rose-red 

K&mmererite 
(Chrome  Chlorite) 
(See  p.  75) 

H8(Mg,Fe)6(Al,Cr)2 
Si3018 

ign.;  decomposed  by  HC1  w.  separation  of  sil.  or  yel.  WO3  powder 


255 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Wh.,  yel., 
grn.,  brn., 
redh. 

Vitreous  to 
adamant. 

4|-5 

5.9-6.1 

Tetr.:  xls.  like 
oct.,  graii 

C.  4,  pyram.,  49J°,  80° 
F.  uneven,  conch. 

Bluish-grn., 
grnh-blue, 
brn.,  blk. 

Vitreous, 
earthy 

2  -3 

2.0-2.2 

Amorph.,  comp. 

F.  conch,  to  uneven 

Pale  to  deep 
grn.,  yelh. 

Dull  to 
resinous 

1  -4 

2.3-2.8 

Amorph.,  botry., 
comp. 

F.  uneven,  conch. 

Olive-grn., 
blkh-grn., 
yelh-grn.,  wh. 

Greasy, 
waxy, 
silky 

3  -4 

2.5-2.6 

Comp.,  fibr. 

F.  conch.,  splint. 
Fibers  flex.,  tough 

Yelh.,  wh., 
grnh.,  redh. 

Resinous 

2  -3 

2  ..0-2  .  2 

Amorph.,  like 
gum  or  resin 

F.  uneven,  conch., 
much  cracked 

Wh.,  to  gryh- 
wh. 

Dull 

2  -1\ 

1.0-2.0 

Compact;  earthy 

F.  uneven,  conch. 

Wh.,  gry., 
cols. 

Vitreous 

5^-6 

2.4-2.5 

Iso.;  us.  trapezo., 
Fig.  3 

F.  uneven,  conch. 

Wh.,  gry., 
grnh.,  yelh., 
bluish,  redh. 

Pearly, 
waxy, 
dull 

1  -2 

2.0-2.2 

Mass.;  earthy 

F.  uneven 

alk.  after  ign.;  insol.  in  HC1;  scratched  w.  knife 


Wh.,  grn.,  yel., 
red,  brn., 
blk. 

Resinous  to 
adamant 

3  1-4 

3.9-4.1 

Tso.  tetrh.;  gran., 
comp. 

C.  6,  dodec.  per.,  60°, 
90°,  120° 
F.  con"h. 

Bnh-blk. 

Resinous 

3|-4 

3.9-4.0 

Hex.  hemimor.  ; 
fibr. 

F.  uneven,  splintery 

Grn.  of  various 
shades 

Vitreous  to 
pearly 

1  -1\ 

2.6-3.0 

Mon.;  scaly, 
foliated 

C.  1,  basal,  per. 
Thin  flakes  flex. 

Rose-red  to 
deep  red 

Vitreous  to 
pearly 

1  -2§ 

2.6-3.0 

Mon.;  scaly, 
foliated 

C.  1,  basal,  per. 
Thin  flakes  flex. 

256 


SECTION  30. — Continued.     Nonmctallic  luster;  fus.  above  5; 


Name. 

Composition. 

Micaceous 
—  Con- 
cluded 

Flakes  brittle; 
H2O  in  c.t. 

Whitens  and  fus.  w.  dif  . 
on  thin  edges 

MARGAKITE 
(Brittle  Mica) 
(See  p.  32) 

HjCaAUSijOi, 
(Some  Fe,  Na,  K) 

Greasy 
feel; 

very  soft 

A  little  H2O  in 
c.t.  on  intense 
ign.  (Cp.  kao- 
linite  and  baux- 
ite, below) 

Al  reac.  w.  Co(NO3)2  on 
-ch.;    radiated  variety 
exfoliates  greatly  b.b. 

PYROPHYLLITE 

(Agalmatollte) 
(See  p.  29) 

H2Al2(Si03)4 

Mg  reac.  w.  Co(NO3)2 
onch.;  sectile 

TALC 

(Steatite:  Soapstone) 
(See  p.  29) 

H2Mg3(SiO3)4 

Much  H2O  read- 
ily given  in  c.t. 

Like   butter  or  cheese; 
brittle  when  dry;    de- 
composed by  H2SO4 

Saponile 

Mg4Al(OH)2(SiO3)5- 
14H2O 

P  reac.  w.  am.  mol.  after  fus. 
w.  soda;  us.  pale  blue-grn. 
flame 

Monazite  us.  transp.  or 
transl.;     Xenotime   is 
opaque 

MONAZITE 

(See  p.  99) 

(Ce,La,Nd,Pr)PO4 
(Often  Th.  Yt) 

XENOTIME 
(See  p.  81) 

YPO4 

(Er;  somet.  Ce  and  Th) 

Al  reac.  w.  Co(NO3)2  on 
ch.;     us.    radiated    or 
globular 

WAVELLITE 
(See  p.  122) 

(A1(OH)3(P04)2-5H20 
(F  Iso.  w.  OH) 

Blue  col.;    b.b.   swells, 
loses  col.  and  crumbles 

Lazulite 
(See  p.  124) 

(Mg,Fe)(A10H)2 
(P04)2 

Cu   flame;     in   c.t.   de- 
crepitates, yields  H2O, 
turns  brn.  or  blk. 

TURQUOIS 

(See  p.  124) 

A12(OH)3PO4-H2O 
(Some  Cu) 

Fus.  to  clear  glass  w.  equal 
amt.  of  soda  on  Pt  wire 

H2O  in  c.t.  at  high  temp. 

OPAL 

(See  p.  54) 

SiO2-nH2O 

Al  reac.  w.  Co(NO3)2  on  ch. 

Little  or  no  H2O  in  c.t. 
H4-5    lengthwise;  6- 
7  crosswise 

CYANITE 

(Dlsthene) 
(See  pp.  109,  113) 

(AlO12SiO3,  or 
Al2SiO5 

H20 

in 
c.t. 

Decrep.  b.b.  ;  SO2 
and  acid  H2O 
at  high  temp, 
in  c.t. 

ALUNITE 
(See  p.  52) 

KA13(OH)6(S04)2 
(Na  Iso.  w.  K) 

I  nsol  .  sil  .  skeleton 
in  s.ph.bd.;  us. 
clay-like,  com- 
pact, or  mealy 

KAOLINITE 

(Kaolin:  Porcelain  Clay) 
(See  p.  47) 

H4Al2Si20» 

Wholly     sol.     in 
s.ph.  bd.  (Baux- 
ite    mark     on 
glass        with 
heavy  pressure, 
adheres  firmly) 

BAUXITE 

(See  p.  47) 

Mixture  A1O-  OH  and 
Al(OH)j 
(Often  Fe,  SI,  Ca,  Mg) 

GlBBSITE 
(Hydrargllllte) 
(See  p.  50) 

A1(OH)3 

not  alk.  after  ign.;  insol.  in  HC1;  scratched  w.  knife 


257 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Pink,  gry., 
wh.,  yelh. 

Vitreous; 
C.  pearly 

3*-4^ 

3.0-3.1 

Mon.;  scaly, 
micac.,  gran. 

C.  1,  basal,  per.;  thin 
flakes  brittle 

Wh.,  apple-grn., 
gry.,  yel., 
brn. 

Pearly  to 
dull 

1  -2 

2.8-2.9 

Orth.;  fol.,  fibr., 
radial 

C.  1,  basal,  per.;  thin 
flakes  flexible 
F.  uneven,  splint. 

Apple-grn., 
gry.,  wh. 

Greasy  ; 
C.  pearly 

1  -21 

2.5-2.8 

Mon.  us.;  fol., 
comp. 

C.  1,  basal,  per.;  sectile 
F.  uneven 
Flakes  flexible 

Wh.,  yelh., 
grnh.,  bluish, 
redh. 

Greasy 

0  -1 

2.2-2.3 

Amorph.; 
comp. 

Yelh-grn.  to 
yelh-  and 
redh-brn. 

Resinous 

5-5J 

4.9-5.3 

Mon.;  sands, 
dissem. 

P.  1,  basal 
F.  uneven,  conch. 

Yelh.  to  redh- 
brn. 

Resinous  to 
vitreous 

4  -5 

4.4-4.6 

Tetr.;  xls., 
comp.,  dissem. 

C.  2,  prism,  per.,  90° 
F.  uneven,  splint. 

Wh.,  yel.,  grn., 
brn. 

Vitreous  to 
pearly 

3  1-4 

2.3-2.4 

Orth.; 
us.  radial 

C.  3,  pinac.,  73°,  90° 
F.  uneven,  conch. 

Azure-blue 

Vitreous 

5  -6 

3.0-3.1 

Mon.;  xls.,  gran. 

C.  2,  prism.,  poor 
F.  uneven 

Blue,  bluish- 
grn.,  grn. 

Waxy 

5  £-6 

2.6-2.8 

Tri.;  us.  comp., 
incrust. 

F.  conch. 

Cols.,  red,  yel., 
grn.,  blue,  gry. 

Vitreous  to 
resinous 

5HH 

2.1-2.2 

Amorph.,  botry. 

F.  conch. 

Blue,  grn., 
gry.,  wh.; 
often  streaked 

Vitreous  to 
pearly 

4  -5 

6  -7 

3.5-3.7 

Tri.;  us.  bladed 

C.  2,  pinac.per.,  74°,  106° 
P.I,  basal 
F.  splint. 

Wh.,  gryh., 
redh. 

Vitreous 

3  §-4 

2.6-2.8 

Hex.  rhom. 

C.  1,  basal 
F.  uneven 

Wh.,  yelh., 
redh.,  brnh. 

Pearly, 
dull 

1  -2| 

2.6 

Mon.;  us.  clay- 
like,  friable 

F.  earthy 

Wh.,  gry.,  yel., 
red 

Dull, 
earthy 

1-3 

2.4-2.6 

Mass.:  clay-like, 
pisolitic 

F.  earthy 

Wh.,  gryh., 
grnh.,  redh. 

Vitreous, 
dull 
C.  pearly 

2|-8| 

2.3-2.4 

Mon.;  incrust, 
stalac.,  scaly, 
fibr. 

C.  1,  basal,  per.;  thin 
flakes  tough 

258 


SECTION  30— Concluded.     Nonmetallic  luster;  fus. 


Name. 

Composition. 

Blackens  and  gives  H2O  in  c.t. 

Ni  in  borax  bd. 

GARNIERITE 
(Genthlte) 
(See  p.  120) 

H2(Ni,Mg)Si04-nH20 
(Approx.) 

W  in  s.ph.  bd.;  yel.  WO3 
res.  in  boiling  HCl 

Ca  renc.  w.  am.  oxalate 
in  HC1  sol. 

SCHEELITE 

(See  p.  89) 

CaWO4 

(TJs.  also  Mo;  somet.  Cu) 

S.  ph.  bd.  in  o.f.  grnh.  hot, 
cols,  cold;  in  r.f.  grnh.  hot, 
violet-blue  cold 

Ti  reac.  w.  H2O2 

Perorskite 
(Perofsklte) 
(See  p.  91) 

CaTiO3 
(Fe  lao.  w.  Ca) 

Cb  reac.  after  fus  w.  borax 

Turns  yel.  and  gives  H?O 
1    in  c.t. 

Yttrotantalite 

(Ca,Fe)(Y,Er) 
(Ta,Cb)4016-4H20 
(Also  us.  Ce.  TJ.  and  W) 

Slight  reac.  for  Cb 

Microlite 

Ca2Ta2O7 
(Us.  also  Cb,  Na,  Mg,  F, 
H) 

SECTION  31.    Nonmetallic  luster;   fus.  above  5;    not 


Become  mag.  on  ign. 

Slowly  and  dif.  sol.  in  HC1 

IRON  ORES 

(See  Sec.  12,  p.  218) 

Cr  in  s.ph.  bd.  (Cp.  picotite) 
p.  296 

CHROMITE 

(Chromic  Iron) 
(See  p.  133) 

FeCr2O4 
(Mg  iso.  w.  Fe; 
Al  and  Fe'"  Iso.  w.  Cr) 

Cleav.  1  direction,  per.;  often 
has  a  metalloidal  luster 

HYPERSTHENE 
(See  p.  59) 

(Mg,Fe)Si03 
(Somet.  Al) 

Cleav.  and  prism  angles  54° 
and  126°;  us.  slender 
prisms,  often  fibrous  (as- 
bestos) 

Anthophyllite 
(Asbestos  In  part) 
(See  p.  62) 

(Mg,Fe)Si03 
(Somet.  also  Al) 

H2O  in  Rosettes;  foli- 
c.t.  on  ated  ;  thin  scales 

Chloritoid 
(See  p.  60) 

H2FeAl2SiO7 
(Some  Mg,  somet.  Mn) 

ign.            Oblong      shining 
scales  and  plates 

Ottrclite 
(See  p.  60) 

H2(Fe,Mn)(Al,Fe)2 
Si209 

Blackens  b.b.  but  does 
not  become  mag. 

Cleav.  and  prism  angles  88° 
and  92°;  often  has  bronzy, 
metalloidal  luster.  (Cp. 
turquois,  next  page;  also 
minerals  above,  which  do 
not  always  become  mag.) 

ENSTSATITE 
(Bronzlte) 
(See  p.  36) 

MgSiO3 
(FeO  up  to  12%) 

Whitens  b.b.  and  fus. 
slightly  on  intense  ign. 

B  flame  w.  Turner's  flux  on 
Pt  wire  ;  pyro-electric  ;  often 
curved  triangular  cross-sec- 
tion. Achroite  cols.,  indico- 
lite  blue,  rubellite  red 

TOURMALINE 

(Schorl:  Achroite; 
Indlcollte; 
Rubellite) 
(See  p.  74) 

R»Als(BOH)2(SiO6) 
(R  =  Mg.  Fe,  Ca,  Na, 
K  LI,  (often  some  F) 

above  5;  not  alk.  after  ign.;  insol.  in  HC1;  scratched  w.  knife. 


259 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Pale  to  deep 
grn.,  yelh. 

Dull  to 
resinous 

1  -4 

2.3-2.8 

Amorph.;  botry., 
comp. 

F.  uneven,  conch. 

Wh.,  yel.,  grn., 
brn.,  redh. 

Vitreous  to 
adamant. 

44-5 

5.9-6.1 

Tetr.;  xls.  like 
oct.  ;  gran. 

C.  4,  pyram.,  49J°,  80° 
F.  uneven 

Yel.  and  brn. 
to  blk. 

Adamant  to 
submet. 

5f-6 

4.0 

Iso.  cubes, 
Fig.  5,  striated 
grains 

C.  3,  cubic,  90° 
F.  uneven 

Yel.  to  brn. 
and  blk. 

Vitreous  to 
submet. 

5  -5* 

5.5-5.9 

Orth.; 
us.  prism. 

F.  conch. 

Pale  yel.  to 
brn. 

Resinous 

M 

5.5-G.l 

Iso.;  us.  oct., 
Fig.  1 

F.  conch. 

alk.  after  ign.;  insol.  in  HC1;  not  scratched  w.  knife 


Fe-blk  to 
brnh-blk. 

Dull  to 

submet. 

5$ 

4.3-4.6 

Iso.;  us.  comp., 
gran. 

F.  uneven,  conch. 

Grnh-blk.  to 
brn.  and 
bronze 

Pearly  to 
bronzy 

5  -6 

3.3-3.5 

Orth.;  fol.,  gran. 

C.  1,  pinac.  per. 
F.  uneven 

Gry.,  clove-brn., 
grn. 

Vitreous; 
C.  pearly 

5  -6 

3.0-3.2 

Orth.  ;  us.  fibr., 
lamellar 

C.  2,  prism,  per.,  544° 
F.  splint. 

Dk.  gry.,  grn., 
grnh-blk. 

Pearly 

6  -7 

3.5-3.6 

Tri.;  us.  fol., 
scaly 

C.  1,  basal,  per.; 
brittle 

Grnh-gry., 
blk. 

Vitreous 

6  -7 

3.2-3.3 

Tri.,  oblong 

plates 

C.  1,  basal,  per. 

Yelh.,  gry., 
brn.,  grn. 

Pearly  to 
bronzy 

5  -6 

3  .  1-3  .  3 

Orth.;  us 
lamellar,  gran. 

C.  2,  prism.,  88° 
F.  uneven 
P.  1,  pinac. 

P>rn.,  grn., 
blue,  red, 
pink,  wh., 
cols. 

Vitreous 

7  -7J 

3.0-3.2 

Hex.  rhom. 
hemimorph. 
Fig.  58 
prism. 

F.  conch.  to  uneven 

260 


SECTION  31.— Continued.     Nonmetallic  luster;  f us.  above  5; 


Name. 

Composition. 

Whitens    b.b.    and    fus. 
slightly  on  intense  ign. 
—  Concluded 

Whitens  at  red  heat;  gives  a 
little  H2O  in  c.t.  on  intense 
ign.  (Cp.  the  next  8  miner- 
als, which  also  give  H2O) 

BERYL 

(Emerald,  bright  grn.; 
Aquamarine,  pale) 
(See  p.  127) 

Gl3Al2(Si03)6 
(A  little  H;  somet.  Na, 
LI,  Ca) 

H2O  in  c.t.  on  intense 
ign.  if  not  before.  (Cp. 
beryl,  above) 

(Turquois  and  diaspore 
decrep.,  and  former 
turns  brn.  or  blk.) 

Cu  flame;  P  reac.  w.  am. 
mol.  after  fus.  w.  soda 

TURQUOIS 
(See  p.  124) 

A12(OH)3PO4-H2O 
(Some  Cu) 

Al  reac.  w.  Co(NO3)2  on  ch. 

DlASPOBE 

(See  p.  33) 

A1O-OH 
(Some  Fe) 

A  little  H2O  on  intense  ign.  in 
c.t.  Staurolite  prismatic 
and  often  twinned.  (Cp. 
polycrase,  page  298,  which 
gives  a  little  H20) 

COKDIEBITE 
(lollte) 
(See  p.  108) 

(Mg,Fe)4Al8(OH)2 
(Si2O7)5 

STAUROLITE 
(Staurotlde) 
(See  p.  103) 

Fe(AlO)4(AlOH) 
(Si04)2 
(Felso.w.  Al;  Mgw.Fe) 

Fus.  w.  equal  amt.  of  soda  on 
Pt  wire  to  clear  glass.  Hya- 
lite is  cols,  and  transp. 

OPAL 

(Hyalite) 
(See  p.  54) 

SiOrnH2O 

May  become  mag.  Chlori- 
toid  us.  foliated  or  hex. 
plates  and  scales;  ottrelite 
oblong  shining  scales  and 
plates 

Chloritoid 
(See  p.  60) 

H2Fe,Al2SiO7 

(Some  Mg,  somet.Mn) 

Ottrelite 
(See  p.  60) 

H2(Fe,Mn)(Al,Fe)., 
Si2O9 

Turns  yel.  in  c.t.  ;  Cb  reac. 
after  fus.  w.  borax 

Ytlrotantalite 

(Ca,Fe)(Y,Er) 
(Ta,Cb)4Oifj-4H2O 
(Also  us.  Ce,  U,  and  W) 

Al  reac.  w.  Co(NO3)2  on 
ch. 

F  reac.  w.  NaPO3  (powdered 
s.ph.  beads)  in  c.t. 

TOPAZ 
(See  p.  80) 

Al2(F,OH)2Si04 

Xls.  us.  stout  rectangular 

ANDALUSITE 
(Chlastollte) 
(See  p.  38) 

Al2SiO5,  or 
Al(AlO)SiO4 

Us.  fibrous  or  slender  xls. 

SlLLIMANITE 
(Flbrollte) 
(See  p.  33) 

Al2SiO5,  or 
Al(AlO)SiO4 

Us.bladedxls.;  scratched  by 
knife  parallel  to  cleav.  but 
not  at  right  angles  to  cleav. 

CYANITE 

(Dlsthene) 
(See  pp.  109,  113) 

(AlO)2SiO3,  or 
Al2Si05 

Extremely  hard.  Alexandrite 
is  grn.  by  daylight  (and  by 
incandescent  gas  light)  ; 
red  by  lamplight 

CHBYSOBEBYL 
(Alexandrite) 
(See  p.  114) 

G1A1204 

Extremely  hard.  Emery  con- 
tains magnetite,  hematite, 
or  spinel  intimately  mixed 
w.  corundum 

CORUNDUM 

(Sapphire,  blue;  Ruby, 
red;    Emery,  black) 

(See  p.  45) 

A1203 

not  alk.  after  ign.;  insol.  in  HC1;  not  scratched  w.  knife 


261 


Color. 

Streak. 

Hard- 
ness. 

Specific 
Gravity. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Grn.,  blue, 
yel.,  pink, 
cols. 

Vitreous  to 
resinous 

7*-8 

2.6-2.8 

Hex.;  us.  prism. 
Fig.  49 

F.  conch  to  uneven 

Blue,  bluish- 
grn.,  grn. 

Waxy 

5  1-6 

2.6-2.8 

Tri.  ;  us.  comp., 
incrust. 

F.  conch. 

Wh.,  gry.,  yelh., 
grnh.,  brn. 

Pearly  to 
vitreous 

6  -7 

3.3-3.5 

Orth.,  scaly, 
bladed 

C.  1,  pinac.  per. 
F.  conch. 

Lt.  todk.  blue; 
rarely  cols. 

Vitreous 

7  -7| 

2.6-2.7 

Orth.;  pseudo 
hex.  xls.  ;  gran. 

C.  1,  pinac. 
F.  conch.,  uneven 
P.  1,  basal 

Yelh-brn., 
redh-brn.  to 
brnh-blk. 

Resinous  to 
vitreous 

7-7J 

3.6-3.8 

Orth.; 
Figs.  33-31 
prisms,  twins 

C.'  1,  pinac.,  poor 
F.  uneven,  conch. 

Cols.,  red,  yel., 
grn.,  blue, 
gry. 

Vitreous  to 
resinous 

SMi 

2.1-2.2 

Amorph., 
botry. 

F.  conch. 

Dk.  gry.,  grn., 
grnh-blk. 

Pearly 

6^ 

3.5-3.6 

Tri.;  us.  fol. 

C.  1,  basal,  per.; 
flakes  brittle 

Grnh-gry., 
blk. 

Vitreous 

6  -7 

3.2-3.3 

Tri. 

C.  1,  basal,  per. 

Yel.  to  brn. 
and  blk. 

Vitreous  to 
submet. 

5  -5| 

5.5-5.9 

Orth.; 
us.  prism. 

F.  conch. 

Cols.,  wh.,  yel., 
pink,  bluish, 
grnh. 

Vitreous 

8 

3.4-3.6 

Orth.;  prism., 
pebbles,  comp. 

C.  1,  basal,  per. 
F.  uneven,  conch. 

Flesh-red, 
redh-brn., 
olive-grn. 

Vitreous 

6I-7J 

3.1-3.2 

Orth.  ;  us.  prism. 

C.  2,  prism.,  89° 
F.  uneven 

Hair-brn., 
gry.,  gryh.- 
grn. 

Vitreous 

6-7 

3.2-3.3 

Orth.;  fibr., 
radiating 

C.  1,  pinac.,  per. 
F.  uneven,  splint. 

Blue,  grn., 
gry.,  wh. 

Vitreous  to 
pearly 

4  -5 

6  -7 

3.5-3.7 

Tri.;  us.  bladed 

C.  2,  pinac.  per.,  74° 
P.  1,  basal 
F.  splint. 

Yelh-grn., 
asparagus-grn. 
to  emerald- 
grn. 

Vitreous 

81 

3.5-3.8 

Orth.;  us.  tab.  or 
pseudo-hex, 
twins 

C.  2,  dome,  60° 
F.  uneven,  conch. 

Wh.,  gry., 
pink,  red, 
yel.,  grn., 
blue,  brn.,  blk. 

Adamant, 
to  vitreous 

9 

3.9-4.1 

Hex.  rhom.; 
rough  xls., 
gran.,  comp. 

P.  basal  and  rhom., 
86°,  94° 
F.  uneven,  conch. 

262 


SECTION  31.— Continued.     Nonmetallic  luster;  fus.  above  5; 


Name. 

Composition. 

Cr  in  s.ph.  bd. 

Col.  blk.;  st.  dk.  brn.;  bd. 
shows  Fe  reac.  while  hot 
and  Cr  on  cooling 

CHROMITE 
(Chromic  Iron) 
(See  p.  133) 

FeCr2O4 
(Mglso.w.Fe;  Alw.Cr) 

Dk.  yelh-brn.  to  grnh-brn. 
Xls.  us.  octahedrons 

Pictotote 
(Chrome  Spinel) 
(See  p.  127) 

(Fe,Mg)(Cr,Al)204 

Insol.  skeleton  of  sil.  remains 
in  bd.     Mineral  green 
(Cp.  Garnets,  p.  244) 

Uvarovite 
(Ca-Cr  Garnet) 
(See  p.  102) 

Ca3Cr2(SiO4)3 
(Al  Iso.  w.  Cr) 

Little  or  no  Cr,  but  fine 
powder  wholly  sol.  in 
s.ph.  bd.  (no  silica) 

Xls.  us.  octahedrons,  often 
twins;  dark  varieties  react 
forFe 

SPINEL 
(Spinel  Ruby,  red) 
(See  p.  127) 

MgAl204 
(Fe.  Mn  Iso.  w.  Mg; 
Fe,  Cr  Iso.  w.  Al) 

Wh.  ZnO  subl.  w.  soda  and 
borax  on  Pt  wire;  grn.  w. 
Co(NO3)2.  (See  p.  189) 

Gahnite 
(Zinc  Spinel) 
(See  p.  127) 

ZnAl2O4 
(Mn,  Fe  Iso.  w.  Zn; 
Fe  w.  Al) 

Mag.  mass  when  fused  w.  a 
little  soda  on  ch. 

Hercynite 
(Iron  Spinel) 
(See  p.  127) 

FeAl204 

Fe  chiefly  ferrous 

Pleonaste 
(Mg-Fe  Spinel) 
(See  p.  127) 

(Mg,Fe)Al,O4 

Fe.  chiefly  ferric 

Chlorospinel 
(See  p.  127) 

Mg(Al,Fe)2O4 

Ti  reac.  w.  H2O2 

Xls.  us.  prismatic,  often  very 
slender  and  twinned 

RUTILE 

(See  p.  72) 

Ti02 

(Us.  a  little  Fe) 

Xls.  us.  pyramids 

Octahedrite 
(Anatase) 
(See  p.  68) 

Ti02 

Xls.  often  tabular 

Brookite 
(See  p.  72) 

TiO2 

Metallic  Sn  w  Zn  and 
HC1 

Wh:  subl.  SnO2  on  intense 
ign.  w.  soda  on  ch. 

CASSITERITE 

(Tin  Stone) 
(See  p.  100) 

SnO2 
(Somet.  Fe,  Ta) 

Sp.gr.  above  4;  Zr  test 
w.  turmeric 

Glows  w.  wh.  light  on  intense 
ign.  Hyacinth  is  transp.  red 
or  brown 

ZIRCON 

(Hyacinth) 
(See  p.  56) 

ZrSiO4 
(Us.  a  little  Fe) 

Fus.  w.  equal  amt.  of 
soda  on  Pt  wire  to 
clear  glass 

(Concluded  next  page) 

Xls.  us.  hex.  prisms;  ame- 
thyst, purple 

QUARTZ 

(Rock  Crystal; 
Amethyst) 

(See  p.  55) 

Si02 

Dense,  botryoidal,  mammil- 
lary,  banded  (agate) 

CHALCEDONY 

(Agate,  Jasper.  Chert, 
Flint) 
(See  p.  55) 

SiO2 

not  alk.  after  ign.;  insol.  in  HC1;  not  scratched  w.  knife 


263 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Fc-blk.  to 
brnh-blk. 

Dull  to 
submet. 

5J 

4.3-4.6 

Iso.  ;  us. 
gran.,  comp. 

F.  uneven,  conch. 

Yelh.  or  grnh- 
brn.  to  brnh- 
blk. 

Pitchy  to 
submet. 

7M 

4.0-4.1 

Iso.;  us.  comp., 
dissem. 

F.  uneven,  conch. 

Emerald-grn. 

Vitreous 

1\ 

3.4-3.5 

Iso.;  us. 
small  xls. 

F.  conch.,  uneven 

Red,  lavender, 
blue,  grn., 
brn.,  blk. 

Vitreous 

8  -8J 

3.5-3.6 

Iso.;  us.  oct., 
Fig.  1;  gran. 

F.  conch. 

Dk.  grn.,  brn. 
to  blk. 

Vitreous 

7^-8 

4.0-4.6 

Iso.;  us.  oct., 
Fig.  1;   gran. 

F.  conch.,  uneven 

Blk. 

Vitreous 

7i-8 

3.9-4.0 

Iso.;  us.  comp. 

F.  conch. 

Dk.  grn.,  blue 
brn.  to  blk. 

Vitreous 

7J-8 

3.5-3.6 

Iso.;  us.  oct., 
Fig.  1 

F.  conch. 

Grass-grn. 

Vitreous 

7M 

3.6 

Iso.;  us.  oct.; 
Fig.  1 

F.  conch. 

Redh-brn.  to 
blk.  and  yelh. 

Adamant.  ; 
submet. 

6  -7 

4.1-4.3 

Tetr.;  us.  xls., 
twins 

C.  2,  prism.,  poor 
F.  uneven 

Brn.  to  dk-blue 
and  blk. 

Adamant., 
submet. 

5}-6 

3.8-3.9 

Tetr.  ;  xls.  us. 
pyram., 
somet.  tabular 

C.  5,  basal  and  pyram., 
82°,  111° 
F.  uneven 

Hair-brn  to  blk. 

Adamant., 
submet. 

5^-6 

3.9-4.1 

Orth.:  us.  xls., 
pseudohex. 

F.  uneven 

Brn.  to  blk.; 
rarely  yel., 
red,  gry.,  wh. 

Adamant. 

6  -7 

6.8-7.1 

Tetr.,  gran.; 
twins, 
Fig.  29 

F.  uneven 

Cols.,  gry., 
grn.,  brn., 
red 

Adamant. 

1\ 

4.5-1.8 

Tetr.;  us.  xls., 
dissem. 

F.  conch. 

Cols.,  wh.,  yel., 
red,  grn., 
blue,  brn., 
blk. 

Vitreous  to 
greasy 

7 

2.65 

Hex.  rhom.;  us. 
prism,  xls.; 
gran. 

F.  conch. 

Wh.,  gryh., 
bnh.,  to  blk. 

Vitreous, 
waxy,  dull 

7 

2.6-2.64 

Cryptocrystalline, 
dense 

F.  conch. 

264 


SECTION  31.— Concluded.     Nonmetallic  luster;  fus.  above  5; 


Name. 

Composition. 

Fus.  w.  equal  amt.  of 
soda  on  Pt  wire  to 
clear  glass  —  Concluded 

A  little  H2O  in  c.t.  at  high 
temp. 

OPAL 

(See  p.  54) 

SiO2-nH2O 

Xls.  us.  thin  hex.  plates 

Tridymite 
(See  p.  56) 

SiO, 

Wh.  enamel  w.  soda; 
slowly  sol.  in  borax  to 
clear  glass 

Dull  blue  w.  Co(NO3)2  on  ch. 

PHENACITE 
(See  p.  92) 

Gl2SiO4 

Distinct  cl.,  2  direc.  at 
90°  or  nearly  90° 

Fus.  4-5 

FELDSPARS 
(See  Sec.  23,  p.  238) 

Cb  reac.  after  fus.  w. 
borax 

Us.  Mn  reac.  in  soda  bd. 
Str.  dk.  red  to  blk. 

COLUMBITE 

(See  p.  134) 

(Fe,Mn)Cb2O6 
(Also  Ta  and  some  Sn 
and  W) 

Dull  exterior  ;  str.  pale  brn. 

Fergusonite 
(See  p.  133) 

(Y,Er,Ce,U) 
(Cb,Ta)O4 

Glows  on  ign.  and  becomes 
lighter  col.  ;  decrepitates 

Polycrase 

Uncertain:  Cb,  Ti, 
Y,  Er,  Ce,  Fe,  H,  O 

and  gives  trace  of  H2O  in 
c.t. 

Little  or  no  Cb;  Mn  in 
soda  bd. 

Fe  in  s.ph.  bd.  ;  very  heavy 
(G.  above  6) 

Tantalite 
(See  p.  134) 

(Fe,Mn)Ta2O6 
(Cb  Iso.  w.  Ta;   slight 
Sn  and  W) 

Extremely  hard;  not 
affected  by  acids  or 
alkalis;  burns  in  O 

Xls.  us.  octahedrons  w. 
curved  faces  and  brilliant 
adamantine  luster.  Bort, 
rough  rounded  forms,  con- 
fused xln.  ;  carbonado, 
massive,  dark  gray  to 
black 

DIAMOND 

(Carbonado; 
Carbon;  Bort) 

(See  p.  45) 

C 

(Slight.  ash  In  Carbonado) 

not  alk.  after  ign.;  insol.  in  HC1;  not  scratched  w.  knife 


265 


Color. 

Luster. 

Hard- 
ness. 

Specific 
Gravity. 

Crystallization 
and  Structure. 

Cleavage  and 
Fracture. 

Cols.,  red,  yel., 
grn.,  blue, 
gry. 

Vitreous  to 
resinous 

5HH 

2.1-2.2 

Amorph., 
botry. 

F.  conch. 

Cols.,  wh. 

Vitreous 

7 

2.3 

Hex.;  minute 
tabular 

F.  conch. 

Cols.,  wh., 
yel.,  rose, 
bra. 

Vitreous 

7|-8 

2.9-3.0 

Hex.  rhom.; 
us.  xls. 

C.  3,  prism.,  60°,  120° 
F.  conch. 

Fe-blk.  to  gry. 
and  brnh-blk. 

Resinous  to 
submet. 

6 

5.3-6.5 

Orth.;  short 
prism,  xls. 

C.  1,  pinac.,  poor 
F.  uneven,  conch. 

Brnh-blk. 
str.  pale  brn. 

Brilliant 
vitreous  to 
submet. 

5S-6 

4.3-5.8 

Tetr.; 
us.  comp. 

F.  uneven,  conch. 

Brnh-blk.  to 
blk. 
Str.  gryh.  brn. 

Vitreous  to 
resinous 

5  -6 

5.0-5.1 

Orth.; 
us.  prism. 

F.  conch. 

Blk 

Resinous  to 
submet. 

6 

6.5-7.3 

Orth.,  short 
prism,  xls. 

F.  uneven,  conch. 
C.  1,  pinac.,  poor 

Cols.,  yel.,  red, 
blue,  gry., 
blk. 

Adamant, 
to  greasy 

10 

3.5 

Iso.;  us.  oct. 
or  hexoct., 
Figs.  1,4 

C.  4,  oct.  per.,  70£°, 
109*° 
F.  conch. 

MINERALS    CLASSIFIED    ACCORDING    TO    CRYSTALLIZA- 
TION, LUSTER,  AND   HARDNESS 

While  arranged  primarily  on  the  basis  of  crystallization,  these  tables  may  also  be 
used  for  the  rapid  determination  of  minerals  by  means  of  their  physical  properties, 
even  without  crystals.  Thus  the  minerals  of  a  given  hardness  are  quickly  found  in 
all  the  groups  and  their  specific  gravities  compared.  In  case  two  or  more  are  found 
to  have  approximately  the  same  hardness  and  specific  gravity,  their  composition  will 
usually  suggest  a  distinctive  test;  or  the  references  to  the  preceding  tables  may  be 
used  for  fuller  comparison  of  both  physical  and  chemical  properties. 

ISOMETRIC 
Metallic  or  Submetallic  Luster 


Hard- 
ness. 

Name. 

Composition. 

Specific 
Gravity. 

Physical 
Tables. 

Blowpipe 

Tables. 

0 

Mercury 

Hg 

13.6 

26 

202 

2  -2i 

ARGENTITE 

Ag2S 

7.2-7.4 

18 

200 

2| 

GALENA 

PbS 

7.4-7.6 

19 

200 

2*-3 

COPPER 

Cu 

8.8-8.9 

138 

202 

2*-3 

SILVER 

Ag 

10.0-12.0 

27 

202 

2*-3 

GOLD 

Au 

15.6-19.3 

139 

202 

2J-3 

HESSITE 

Ag2Te 

8.3-8.5 

27 

206 

3 

BORNITE 

CuiFeS4 

4.9-5.4 

24 

200 

3 

Altaite 

PbTe 

8.1-8.2 

28 

206 

3  -3i 

Amalgan 

(Ag,Hg) 

13.7-14.1 

28 

202 

3  -4 

TETRAHEDRITE 

Cu3SbS3 

4.4-5. 

21 

198 

3  -A 

Tennantite 

Cu3AsS3 

4.4-5. 

21 

196 

3M 

SPHALERITE 

ZnS 

3.9-4. 

88 

200 

3*-4 

CUPRITE 

Cu20 

5.8-6. 

141 

.  204 

3J-4 

PENTLANDITE 

(Fe.Ni)S 

4.6-5. 

25 

202 

3|-4 

ALABANDITE 

MnS 

3.9-4.0 

148 

202 

4-4* 

PLATINUM 

Pt 

14.0-19.0 

29 

210 

4  -5 

Iron 

Fe 

7.3-7.8 

206 

5| 

CHROMITE 

FeCr2O4 

4.3-4.6 

133 

208 

5* 

LlNNAEITE 

(Ni,Co)3S4 

4.8-5.0 

15 

202 

5* 

GERSDORFFITE 

NiAsS 

5.6-6.2 

15 

196 

5J-6 

SMALTITE 

CoAs2 

6.4-6.6 

16 

196 

5^-6 

CHLOANTHITE 

NiAsz 

6.4-6.6 

16 

196 

5|-6i 

MAGNETITE 

FeFe204 

4.9-5.2 

22 

204 

5HH 

FRANKLINITE 

(Fe,Mn,Zn)(Fe,Mn)2O4 

5.1-5.2 

23 

208 

6  -6* 

PYRITE 

FeS, 

4.9-5.2 

26 

200 

6  -7 

Martite 

Fe.03 

4.8-5.3 

134 

204 

6  -7 

Iridium 

Ir 

22  .  6-22  .  8 

29 

210 

Nonmetallic  Luster 


1  -li 
1  -li 

l£ 

CERARGTRITE 
EMBOLITE 

AgCl 
Ag(Cl,Br) 
As2O8 

5.5-5.6 
5.3-5.8 
3.7 

46 
93 

216 
216 
212 

2-2J 
2  -2| 

HALITE 

SYLVITE 

NaCl 
KC1 

2.1-2.6 
1.9-2.0 

39 
39 

224 
224 

CRYSTALLIZATION,   LUSTER  AND   HARDNESS 


267 


ISOMETRIC 

Nonmetallic  Luster — Concluded 


Hard- 
ness. 

Name. 

Composition. 

Specific 
Gravity. 

Physical 

Tables. 

Blowpipe 

Tables. 

2  -21 

Kalinite 

KA1(SO4)2-12H2O 

1.7 

224 

2  -2£ 

Senarmontite 

Sbrf>, 

5.2-5.3 

49 

212 

2  -3 

Bromyrite 

AgBr 

5.8-6.0 

95 

216 

3-J-4 

SPHALERITE 

ZnS 

3.9-4.1 

88 

228 

3M 

CUPRITE 

Cu2O 

5.8-6.1 

141 

214 

3|-4 

ALABANDITE 

MnS 

3.9-4.0 

148 

202 

4 

FLUORITE 

CaF2 

3.0-3.2 

116 

226 

5  -5| 

ANALCITE 

NaAl(SiO3)2-H2O 

2.2-2.3 

53 

232 

5  -5J 

LAZURITE 

Na6Al3S3(SiO4)3 

2.4-2.5 

148 

230 

5  -6 

SODA  LITE 

Na4Al3Cl(SiO4)3 

2.1-2.3 

124 

230 

5* 

COBAI/TITE 

CoAsS 

6.0-6.3 

15 

196 

5* 

URANINITE 

UO3,UO2,Pb,Th,  etc. 

9.0-9.7 

22 

210 

5J 

Noselile 

Na5Al3(SO4)(SiO4)3 

2.2-2.4 

230 

5* 

Microlite 

Ca2Ta2O7 

5.5-6.1 

258 

5J-6 

LEUCITE 

KAl(SiO3)2 

2.4-2.5 

54 

254 

5  1-6 

Pcrovskite 

CaTiO3 

4.0 

91 

258 

5J-6 

Hduynitc 

CaNa3Al2(SO4)(SiO4)3 

2.4-2.5 

230 

62-6 

Dan&lite 

Gl3R4S(SiO4)3 

3.4 

220 

6J-7J 

GARNET 

R"3R'"2(SiO4)3 

3.4-4.3 

101 

244 

PYROPE 

Mg3Al2(SiO4)3 

3.7 

101 

244 

ALMANDITE 

Fe3Al2(SiO4)3 

3.9-4.2 

101 

244 

SPESSARTITE 

Mn3Al2(Si04)3 

4.0-4.3 

101 

244 

GROSSULARITE 

Ca3Al2(Si04)3 

3.5-3.6 

101 

244 

ANDRADITE 

Ca3Fe2(Si04)3 

3.8-3.9 

101 

244 

UVAROVITE 

Ca3Cr2(SiO4)3 

3.4-3.5 

101 

262 

SCHORI.OMITE 

Ca3(Fe,Ti)2(Si,Ti)40)2 

3.8-3.9 

101 

232 

7 

BORACITE 

Mg7Cl2Bi603o 

2.9-3.0 

56 

228 

7|-8 

Pleonaste 

(Mg,Fe)Al204 

3.5-3.6 

127 

262 

7*-8 

Gahnite 

ZnAl2O4 

4.0-4.6 

127 

262 

7*-8* 

SPINEL 

MgAl204 

3.5-3.6 

127 

262 

PLEONASTE 

(Mg,Fe)Al2O4 

3.5-3.6 

127 

262 

CHLOROSPINEL 

Mg(Al,Fe)2O4 

3.6 

127 

262 

GAHNITE 

ZnAl^O4 

4.0^.6 

127 

262 

HERCYNITE 

FeAl204 

3.9-4.0 

127 

262 

PlCOTITE 

fMglFe)(Al,Fe,Cr)2O4 

4.1 

127 

262 

-  10 

DIAMOND 

C 

3.5 

45 

264 

TETRAGONAL 
Metallic  or  Submetallic  Luster 


3M 

CHALCOPYRITE 

CuFeS2 

4.1-4.3 

24 

200 

4 

Slannite 

Cu2FeSnS4 

4.3-4.5 

15 

200 

5  -5* 

Hausmannite 

MnMn2O4 

4.7-4.9 

131 

208 

5^-6 

Octahedrite 

Ti02 

3.8-3.9 

68 

210 

5M 

Fergusonite 

(Y,Er,Ce,U)(Cb,Ta)O4 

4.3-5.8 

133 

210 

6  -6| 

Braunite 

3Mn2O3-MnSiO3 

4.7-4.8 

23 

208 

6  -7 

RUTILE 

TiO2 

4.1-4.3 

72 

210 

Nonmetallic  Luster 

1  -2 

Calomel 

Hg2Cl2 

6.4-6.5 

47 

212 

3 

WULFENITE 

PbMoO4 

6.7-7.0 

96 

214 

4  -5 

XENOTIME 

YPO4 

4.4-4.6 

81 

256 

268 


MINERALS  CLASSIFIED  ACCORDING  TO 


TETRAGONAL 
Nonmetallic  Luster — Concluded 


Hard- 
ness. 

Name. 

Composition. 

Specific 
Gravity. 

Physical 
Tables. 

Blowpipe 
Tables. 

41-5 

SCHEELITE 

CaWO4 

5.9-6.1 

89 

234 

41-5 

APOPHYLLITE 

(H,K)2Ca(Si03)2-H20 

2.3-2.4 

33 

234 

41-5 

Thorite 

ThSiO4 

4.4-5.4 

130 

252 

5 

Melilite 

Na2(Ca,Mg)u(Al,Fe)4 

(Si04)9 

2.9-3.1 

232 

5-51 

Hausmannite 

MnMn2O4 

4.7-4.9 

131 

250 

5  -6 

WERNERITE 

/  n(Ca4Al6Si6O25)          \ 
\  m(Na4Al3Si9024Cl)     / 

2.6-2.8 

44 

234 

51-6 

Octahedrite 

TiO2 

3.8-3.9 

68 

262 

51-6 

Fergusonite 

(Y,Er,Ce,U)(Cb,Ta)O4 

4.3-5.8 

133 

264 

6  -61 

Braunile 

3Mn2O3-MnSiO3 

4.7-4.8 

23 

208 

6  -7 

RUTILE 

TiO2 

4.1-4.3 

72 

262 

6  -7 

CASSITERITE 

SnO2 

6.8-7.1 

100 

262 

8* 

VESUVIANITE 

Ca6Al3(OH(F)(Si04)s 

3.3-3.5 

101 

244 

71 

ZIRCON 

ZrSiO4 

4.5-4.8 

56 

262 

ORTHORHOMBIC 

Metallic  or  Submetallic  Luster 


1  -1J 

Nagyagite 

Au,Pb,Sb,Te,S 

6.8-7.2 

206 

2 

STIBNITE 

Sb2S3 

4.5-4.6 

18 

198 

2 

Bismuthinite 

Bi2S3 

6.4-6.5 

14 

202 

2  -21 

PYROLUSITE 

MnO2 

4.7-4.8 

18 

208 

2  -21 

STEPHANITE 

Ag6SbS4 

6.2-6.3 

18 

198 

2  -3 

JAMESONITE 

Pb2Sb2S5 

5.5-6.0 

14 

198 

2* 

KRENNERITE 

AuAgTe4 

8.3-8.4 

27 

206 

2J-3 

CHALCOCITE 

Cu2S 

5.5-5.8 

19 

200 

21-3 

BOURNONITE 

PbCuSbS3 

5.7-5.9 

20 

198 

21-3 

STROMEYERITE 

AgCuS 

6.2-6.3 

20 

200 

3 

ENARGITE 

Cu3AsS4 

4.4-4.5 

20 

196 

3  -3i 

Zinkenite 

PbSb2S4 

5.3-5.4 

198 

31 

Dyscrasite 

Ag3Sb  to  AgeSb 

9.4-9.9 

"'28' 

198 

31-4 

MANGANITE 

MnO-OH 

4.2-4.4 

130 

208 

5  -51 

GOETHITE 

FeO-OH 

4.0-4.4 

142 

204 

5  -51 

Loellingile 

FeAs2  to  FeaAs4 

7.0-7.4 

15 

196 

51-6 

ARSENOPYRITE 

FeAsS 

5.9-6.2 

16 

196 

51-6 

Brookite 

TiO2 

3.9-4.1 

72 

210 

51-6 

Ilvaite 

CaFe3(OH)(SiO4)2 

4.0-4.1 

22 

206 

6 

COLUMBITE 

(Fe,Mn)Cb2O6 

5.3-6.5 

134 

204 

6 

Tantalite 

(Fe,Mn)Ta2Oc 

6.5-7.3 

134 

210 

6  -6i 

MARCASITE 

FeS2 

4.8-4.9 

26 

200 

Nonmetallic  Luster 

1  -2 

PYROPHYLLITE 

H2Al2(SiO3)2 

2.8-2.9 

29 

256 

1  -2 

CARNAL.  LITE 

KMgCl3-6H2O 

16 

47 

224 

1  -2 

Molybdite 

Fe2(Mo04)3-7m20 

4.5 

92 

228 

11-21 

SULPHUR 

S 

2.0-2.1 

94 

212 

2 

NITER 

KN03 

2.1-2.2 

48 

226 

CRYSTALLIZATION,  LUSTER  AND  HARDNESS 


269 


ORTHORHOMBIC 

Nonmetallic  Luster — Concluded 


Hard- 
ness. 

Name. 

Composition. 

Specific 
Gravity. 

Physical 
Tables. 

Blowpipe 
Tables. 

2  -21 

EPSOMITE 

MgSO4-7H2O 

1.7-1.8 

49 

224 

2  -2§ 

-Au<Mra'<e 

Ca(UOi),(PO4)i-8H«O 

3.1-3.2 

138 

228 

2  -2* 

Goslarite 

ZnSO4-7H2O 

1.9-2.1 

250 

2  -3 

THENARDITE 

Na2SO4 

2.7 

31 

224 

21-34 

BARITE 

BaS04 

4.3-4.6 

39 

226 

3 

ANGLESITE 

PbS04 

6.1-3.4 

40 

214 

3 

Olivenite 

Cu2(OH)AsO4 

4.1-4.6 

146 

216 

3  -3* 

CERUSITE 

PbCO3 

6.4-6.6 

51 

214 

3  -3J 

ANHYDRITE 

CaSO4 

2.9-3.0 

40 

226 

3  -3J 

CELEST1TE 

SrSO4 

3.9-4.0 

40 

226 

3  -3J 

ATACAMITE 

Cu2(OH)3Cl 

3.7-3.8 

147 

214 

3  -4 

WITHERITE 

BaCO3 

4.3-4.4 

51 

226 

3i 

Descloizile 

PbZn(PbOH)VO4 

5.9-6.2 

140 

214 

3M 

ARAGONITE 

CaCO3 

2.9-3.0 

41 

246 

3M 

STRONTIANITE 

SrCO3 

3.7 

34 

246 

3M 

BROCHANTITE 

Cu4(OH)6SO4 

3.9 

147 

216 

3*-4 

WAVELLITE 

(A1OH)3(PO4)2-5H2O 

2.3-2.4 

122 

252 

3M 

SCORODITE 

FeAsO4-2H2O 

3.1-3.3 

122 

218 

3M 

Dufrenite 

Fe2(OH)3PO4 

3  .  2-3  .  4 

218 

4|-5 

CALAMINE 

(ZnOH)2SiO3 

3.4-3.5 

35 

252 

4*-5 

Lithiophilite 

FaMnPO4 

3.4-3.5 

228 

4  1-5 

Triphylile 

LiFePO4 

3.5-3.6 

218 

5 

Glaucodot 

(Co.Fe)AsS 

5.9-6.0 

196 

5  -51 

NATROLITE 

Na  Al(  A1O)  (SiO3)3  •  2H2O 

2.2-2.3 

35 

230 

5  -5J 

GOETHITE 

FeO-OH 

4.0-4.4 

142 

218 

5  -5J 

THOMSONITE 

(Ca,Na2)2Al4(Si04)4 

•5H2O 

2.3-2.4 

53 

230 

5  -6 

ENSTATITE 

MgSiO3 

3.1-3.3 

36 

240 

5  -6 

HYPERSTHENE 

(Fe,Mg)SiO3 

3.3-3.5 

59 

222 

5  -6 

AnthophyUite 

(Mg,Fe)SiO3 

3.0-3.2 

62 

222 

5  -6 

Samarskite 

(Fe,Ca,U02)3(Ce,Y,Er)2 

(Cb,Ta)6O2i 

5.6-5.8 

,    133 

242 

5  -6 

Polycrase 

Cb,Ti,Y,Er,Ce,Fe,H,O 

5.0-5.1 

264 

5J-6 

Tephroite 

Mn2SiO4 

4.0-4.1 

63 

230 

5}-6 

Brookite 

Ti02 

8.9-4.1 

72 

262 

5J-6 

Ihaite 

CaFe3(OH)(SiO4)2 

4.0-1.1 

22 

220 

6 

COLUMBITE 

(Fe,Mn)CbjO« 

5.3-6.5 

134 

242 

6 

Tantalite 

(Fe,Mn)Ta2O6 

6.5-7.3 

134 

264 

6  -61 

PREHNITE 

H2Ca2Al2(Si04)8 

2.8-3.0 

125 

234 

6  -61 

ZOISITE 

Ca2Al3(OH)(SiO4)3 

3.2-3.4 

33 

246 

6  -7 

SlLLIMANITE 

Al(AlO)SiO4 

3.2-3.3 

33 

260 

6  -7 

DlASPORE 

A1O-OH 

3.3-3  5 

33 

260 

6  -7 

Forsterite 

Mg2Si04 

3.2-3.3 

85 

252 

61 

Fayalite 

Fe2SiO4 

3.9-4.1 

85 

220 

6}-7 

OLIVINE 

(Mg,Fe)2Si04 

3.2-3.6 

85 

252 

61-71 

ANDALUSITE 

Al(AlO)SiO4 

3.1-3.2 

38 

260 

7  -71 

STAUROLITE 

Fe(AlO)4(AlOH)(SiO4)2 

3.6-3.8 

103 

260 

7  -71 

CORDIERITE 

(Mg,Fe)4Al8(OH)2 

(Si207)5 

2.6-2.7 

108 

244 

7  -71 

DANBURITE 

CaB2(Si04)2 

3.0 

102 

242 

71-8 

Lawsonite 

CaAl2(OH)4(Si03)2 

3.1 

38 

244 

8 

TOPAZ 

Al2(F,OH)2SiO4 

3.4-3.6 

80 

260 

81 

CHRYSOBERYL 

G1A12O4 

3.5-3.8 

114 

260 

270 


MINERALS   CLASSIFIED  ACCORDING  TO 


MONOCLINIC 
Metallic  or  Submetallic  Luster 


Hard- 
ness. 

Name. 

Composition. 

Specific 
Gravity. 

Physical 
Tables. 

Blowpipe 
Tables. 

U-2 

SYLVANITE 

AuAgTe4 

7.9-8.3 

26 

206 

2  -3 

POLYBASITE 

(Ag,Cu)9SbS« 

6.0-6.2 

19 

198 

t| 

CALAVERITE 

(Au,Ag)Te2 

9.0 

27 

206 

3 

PEARCEITE 

(Ag,Cu)9AsS6 

6.1-6.2 

20 

196 

3  -4 

Melaconite 

CuO 

5.8-6.2 

21 

204 

5 

FERBERITE 

FeWO4 

7.5 

21 

204 

5  -51 

WOLFRAMITE 

(Fe,Mn)WO4 

7.2-7.5 

21 

204 

6  -6 

HORNBLENDE 

Ca.Mg.Fe.Al  silicate 

2.9-3.4 

61 

222 

5}  -6 

ALLANITE 

(Ca,Fe)»(Al,Fe,Ce)i 

(Si04)3 

3.0-4.2 

71 

206 

MONOCLINIC 

Nonmetallic  Luster 

0  -1 

ULEXITE 

NaCaB6O9-H2O 

1.6-1.7 

46 

228 

-U 

VERMICULITE 

Mg.Fe.Al  silicates 

2.3-2.8 

75 

232 

-11 

ANNABEROITE 

Ni3(AsO4)2-8H2O 

3.0-3.1 

120 

218 

-u 

Natron 

Na2CO3-10H2O 

1  4-1.5 

224 

-U 

Kermcsite 

Sb2S2O 

4.5-4.6 

212 

-21 

KAOLINITE 

H4Al2Si2O9 

2.4-2.6 

47 

256 

-21 

TALC 

H2Mg3(Si03)4 

2.5-2.8 

29 

236 

—21 

CHLORITE 

H,Fe,Mg,Al  silicate 

2.6-3.0 

104 

236 

-21 

Kammererite 

H,Mg,Fe,Al,Cr  silicate 

2.6-3.1 

75 

236 

U-2 

GYPSUM 

CaSO4-2H2O 

2.3-2.4 

30 

224 

11-2 

ORPIMENT 

As»S, 

3.4-3.5 

136 

212 

U-2 

VIVIANITB 

Fe3(PO4)2-8H2O 

2.6-2.7 

104 

218 

11-2 

REALGAR 

AsS 

3.5-3.6 

136 

212 

11-2 

MIRABILITE 

Na2SO4-10H2O 

1.4-1.5 

48 

224 

11-2 

AlunoQcn 

A12(SO4)3-18H2O 

1.6-1.8 

250 

11-21 

ERYTHRITE 

Co3(AsO4)2-8H2O 

2.9-3.0 

137 

218 

11-21 

COPIAPITB 

Fe2(FeOH)2(S04)B 

•18H2O 

2.1 

76 

218 

2 

MELANTERITE 

FeSO4-7H2O 

1.9 

120 

218 

2 

Aurichaltite 

(Zn.Cu)6(OH)6(C03)2 

3.5-3.6 

248 

2  -21 

BORAX 

Na2B,O7-10H2O 

1.7 

"36" 

226 

2  -21 

Pharmacolite 

HCaAsO4-2H2O 

2.6-2.7 

49 

228 

2  -3 

MUSCOVITE 

HjKAl,(Si04), 

2.7-3.0 

30 

236 

2  -3 

Paragonite 

H2NaAl?(SiO4)3 

2.8-2.9 

31 

236 

2  -3 

BIOTITE 

(H,K)2(Mg,Fe)2Al2 

(SiO4)3 

2.8-3.1 

58 

236 

2  -3 

PHLOGOPITE 

H2KMg3AKSiO4)3 

2.8-2.9 

106 

236 

2  -3 

LEPIDOLITE 

(Li,K)2Al2(OH,F)2 

(SiO3)3 

2.8-2.9 

31 

236 

2  -3 

Zinnwaldite 

(K,Li)3Fe(AlO) 

Al(F,OH)2(SiO4)3 

2  .  8-3  .  2 

220 

2  -3 

G&y-Lussite 

Na2Ca(CO3)2-5H2O 

1  .  9-2  .  1 

224 

21 

CRYOLITE 

Na3AlF6 

2.9-3.0 

49 

226 

21 

Glauberite 

Na2Ca(SO4)2 

2.7-2.8 

31 

226 

21 

Leadhillile 

Pb4(OH)2(C03)2S04 

6.2-6.5 

31 

214 

21 

Cookeite 

LiAl(F,OH)2(Si03)2 

2.7 

236 

21-31 

GIBBSITE 

A1(OH)3 

2.3-2.4 

50 

256 

21-3 

KAINITE 

KMgClSO4-3H2O 

2.0-2.2 

39 

224 

21-3 

CROCOITK 

PbCrO4 

5.9-6.1 

139 

214 

'CRYSTALLIZATION,  LUSTER  AND  HARDNESS 


271 


MONOCLINIC 

Nonmetallic  Luster — Concluded 


Hard- 
ness. 

Name. 

Composition. 

Specific 
Gravity. 

Physical 
Tables. 

Blowpipe 
Tablea. 

2|-3 

TRONA 

HNa3(CO3)2-2H2O 

2.1-2.2 

32 

224 

2|-3 

Polyhalite 

K2MgCa2(SO4)4-2H2O 

2.7-2.8 

78 

226 

3 

Lepidomelane 

(K,H)2Fe3(Fe,Al)4(SiO4)3 

3.0-3.2 

220 

3  -4 

TALC 

H2Mg,(Si03)4 

2.5-2.8 

29 

236 

3| 

Hydromagnesite 

Mg4(OH)2(C03)3-3H20 

2.1-2.2 

248 

3M 

MALACHITE 

Cu2(OH)2CO3 

3.9-4.0 

147 

214 

3M 

AZURITE 

Cu3(OH)2(CO3)2 

3.7-3.8 

147 

214 

3|-4 

STILBITE 

H4(Ca,Na2)Al2(SiO3)6 

•4H2O 

2.1-2.2 

32 

234 

3M 

HEULANDITE 

H4(Ca)Na2)Al2(SiO3)6 

•3II2O 

2.2 

32 

234 

3M 

LAUMONTITE 

H4,Ca(AlO)2(SiO3)4 

•2HjO 

2.2-2.3 

41 

230 

31-41 

MARGAHITE 

H2CaAl4Si2Oi2 

3.0-3.1 

32 

236 

4 

Barytocalcite 

CaBa(CO3)2 

3.6-3.7 

246 

4  -4J 

COLEMANITE 

HCa(BO2)3-2H2O 

2.3-2.5 

34 

228 

4  -4J 

Phillipsile 

(Ca,K2)Al2(Si03)4 

•5H2O 

2.2 

34 

232 

4* 

HARMOTOME 

H2BaAl2(SiO3)5-4H2O 

2.4-2.5 

34 

52 

4^-5 

PECTOLITE 

HNaCa2(SiO3)3 

2.7-2.8 

52 

234 

4M 

WOLLASTONITE 

CaSiO3 

2.8-2.9 

35 

234 

4*-5 

Tripliie 

R(RF)PO4 

3.4-3.8 



218 

5 

FF.RBERITE 

FeWO4 

7.5 

21 

222 

5 

Mesolite 

Na2Ca2Al3(AlO)3 

(SiOo)9-8H2O 

2.2-2.4 

230 

5 

Herderite 

CaGl(OH,F)PO4 

3.0 

228 

5  -5* 

DATOLITE 

Ca(BOH)SiO4 

2.9-3.0 

53 

230 

5  -5* 

TITANITE 

CaSiTiOs 

3.4-3.6 

82 

234 

5  -5| 

MONAZITE 

(Ce,La,Nd,Pr)PO4 

4.9-5.3 

99 

256 

5-5  i 

HUEBNERITE 

MnWO4 

6.9-7.4 

21 

234 

5  -5J 

Scolecite 

CaAl(AlO)(SiO3)3 

•3H2O 

2.2-2.4 

36 

230 

5  -6 

TREMOLITE 

CaMg3(SiO3)4 

2.9-3.1 

36 

238 

5  -G 

ACTINOLITE 

Ca(Mg,Fe)3(SiO3)4 

3.0-3.2 

110 

238 

5  -6 

HORNBLENDE 

Ca,Mg,Fe,Al  silicate 

2.9-3.4 

61 

222 

5  -6 

DIOPSIDE 

CaMg(SiO3)2 

3.2-3.6 

36 

240 

5  -6 

PYROXENE 

Ca(Mg,Fe)(SiO3)2 

3.2-3.6 

111 

220 

5  -6 

AUGITE 

Ca,Mg,Fe,Al  silicate 

3.2-3.6 

62 

222 

5  -6 

Hedenbergite 

CaFe(SiO3)2 

3.5-3.6 

111 

220 

5  -6 

Jeffersonite 

(Ca,Mn)(Mg,Fe,Zn) 

(SiO3)2 

3.4-3.6 

240 

5  -6 

Lazulite 

(Fe,MK)(AlOH)2(PO4)2 

3.0-3.1 

'"l24 

256 

61-6 

ALLANITE 

(Ca,Fe)2(Al,Fe,Ce)3 

(SiO4)3 

3.0-4.2 

71 

220 

6 

Arfvedsonite 

(Na,K)2CaFeSiO3 

3.4-3.5 

222 

6  -61 

ORTHOCLASE 

KAlSi3O8 

2.5-2.6 

"37 

238 

6  -6| 

CHONDRODITE 

Mg5(F,OH)2(SiO4)2 

3.1-3.2 

100 

252 

6  -6J 

Glaucophane 

NarMg,Fe,Ca)Al(SiO3)3 

3.0-3.1 

112 

238 

6  -6J 

Aeoirite 

NaFe'"(SiO3)2 

3.5-3.6 

63 

222 

6  -6J 

Petalite 

LiAl(Si2O5)2 

2.4-2.5 

242 

6* 

Piedmontile 

Ca2(Al,Mn,Fe)3(OH) 

(SiO4)3 

3.4 

242 

6  -7 

EPIDOTE 

Ca2(Al,Fe)3(OH)(SiO4)3 

3.2-3.5 

79 

222 

6  -7 

SPODUMENE 

LiAl(SiO3)2 

3.1-3.2 

38 

240 

6  -7 

GadoUnite 

FeGl2(YO)2(SiO4)2 

4.0-4.5 

73 

232 

272 


MINERALS   CLASSIFIED  ACCORDING  TO 


TRICLINIC 
Nonmetallic  Luster 


Hard- 
ness. 

Name. 

Composition. 

Specific 
Gravity. 

Physical 
Tables. 

Blowpipe 
Tables. 

0  -1 

Sassolite 

H2BO3 

1.4-1.5 

29 

228 

2J 

CHALCANTHITE 

CuSO4-5H2O 

2.1-2.3 

121 

216 

4  -5 

CYANITE 

(A10)2Si03 

3.5-3.7 

113 

256 

5J-6 

TURQUOIS 

A12(OH)3PO4-H2O 

2.6-2.8 

124 

250 

5J-6J 

RHODONITE 

MnSiO3 

3.4-3.7 

83 

240 

6 

Amblygonite 

Li(AlF)PO4 

3.0-3.1 

37 

242 

6  -6| 

MICROCLINE 

KAlSi3O8 

2.5-2.6 

37 

238 

6  -6* 

PLAGIOCLASE 

/  n(NaAlSi3O8)      (ab)  \ 
\  m(CaA!2Si2O8)    (an)  ] 

2.6-2.8 

37 

238 

ALBITE 

ab-abeani 

2.62-2.64 

37 

238 

OLIGOCLASE 

abean  i-ab3an  i 

2.65-2.67 

37 

238 

ANDESINE 

ab3ani-abiani 

2.68-2.69 

37 

238 

LABRADORITE 

abiani-abians 

2.70-2.72 

37 

238 

BYTOWNITE 

abians-abiane 

2.73-2.75 

37 

238 

ANORTHITE 

abianfi-an 

2.75-2.76 

37 

238 

6  -7 

CYANITE 

(AlO)2SiO3 

3.5-3.7 

113 

256 

6  -7 

AXINITE 

HCa3Al2B(SiO4)4 

3.3-3.4 

80 

242 

6  -7 

Chloritoid 

H2FeAl2SiO7 

3.5-3.6 

60 

222 

6  -7 

Ottrelite 

H2(Fe,Mn)(Al,Fc)jSi40» 

3.2-3.3 

60 

222 

HEXAGONAL 
Metallic  or  Submetallic  Luster 


1  -11 

MOLYBDENITE 

MoSi 

4.7-4.8 

17 

210 

1  -2 

GRAPHITE 

C 

1.9-2.3 

17 

210 

H-2 

COVELLITE 

CuS 

4.6 

17 

200 

li-2 

Tetradymite 

Bi2(Te,S)3 

7.2-7.6 

202 

2  -2-J 

BISMUTH 

Bi 

9.7-9.8 

"27" 

202 

2  -2J 

Tellurium 

Te 

6.1-6.3 

27 

206 

2|-3 

PYRARGYRITE 

Ag3SbS3 

5.8-5.9 

129 

198 

3  -3$ 

MlLI.ERITE 

NiS 

5.3-5.7 

24 

202 

3  -3J 

Antimony 

Sb 

6.6-6.7 

28 

198 

3  -4 

ARSENIC 

As 

5.6-5.7 

28 

196 

31-4* 

PYRRHOTITE 

FeS 

4.5-4.6 

25 

200 

5  -5* 

NlCCOLITE 

NiAs 

7.3-7.7 

25 

196 

5  -6 

ILMENITE 

FeTiOa 

4.5-5.0 

22 

206 

6J-6i 

HEMATITE 

Fe203 

4.9-5.3 

134 

204 

6  -7 

Iridosmium 

Ir.Os 

18.9-21.2 

29 

210 

Nonmetallic  Luster 

0  -1 

CARNOTITB 

(K2)Ca)O-2U2O3-V2O5 

•nH2O 

(?) 

135 

228 

0  -1 

Bearerite 

CuO-PbO-Fe.2O3 

•2SO2-4H2O 

CO 

135 

214 

1  -H 

lodnrite 

Agl 

5.6-5.7 

136 

216 

H-2 

SODA  NITER 

NaNO3 

2.2-2.3 

48 

224 

li-2 

COVELLITE 

CuS 

4.6 

17 

200 

2 

Chalcopfiyllite 

Cu7(OH)8(AsO4)2 

•  10H2O 

2.4-2.7 

216 

2  -2i 

CINNABAR 

HgS 

8.0-8.2 

137 

212 

CRYSTALLIZATION,  LUSTER  AND  HARDNESS 


273 


HEXAGONAL 
Nonmetallic  Luster — Concluded. 


Hard- 
ness. 

Name. 

Composition. 

Specific 
Gravity. 

Physical 
Tables. 

Blowpipe 
Tables. 

2  -21 

PROUSTITE 

Ag3AsSj 

5.5-5.6 

137 

216 

2  -21 

BRUCITE 

Mg(OH)2 

2.3-2.4 

30 

248 

21-3 

PYRARGYRITE 

Ag3SbS3 

5.8-5.9 

129 

216 

21-31 

Jarosite 

KFe3(OH)6(S04)3 

3.1-3.3 

218 

3 

CALC1TE 

CaCO3 

2.7 

40 

246 

3 

VANADINITE 

Pb6Cl(VO4)3 

6.6-7.2 

96 

214 

3  -31 

GREENOCKITE 

CdS 

4.9-5.0 

140 

250 

3  -31 

Hanksite 

9Na2SO4-2Na2CO3-KCl 

2.5-2.6 

224 

31 

Thaumasite 

Ca3SCSiO10-15H2O 

1.8-1.9 

246 

31-4 

PYROMORPHITE 

Pb5Cl(PO4)3 

6.5-7.1 

122 

214 

31-4 

ALUNITE 

KAl,(OH),(SO«)t 

2.6-2.8 

52 

248 

3M 

DOLOMITE 

CaMg(COi)i 

2.8-2.9 

40 

246 

31-4 

SIDERITE 

FeC03 

3.8-3.9 

41 

218 

3M 

MlMETITE 

Pb5Cl(AsO4)3 

7.0-7.3 

97 

214 

31-4 

Wurtzite 

ZnS 

3.9-4.0 

130 

228 

31-4 

Anker  ite 

Ca(Mg,Fe)(CO3)2 

2.9-3.1 

40 

246 

31-41 

MAGNESITE 

MgCO3 

3.0-3.1 

42 

248 

31-41 

RHODOCHROSITE 

MnCO3 

3.4-3.6 

88 

248 

31-41 

Breunnerite 

(Mg.Fe)COs 

3.0-3.2 

42 

248 

4  -4J 

ZINCITE 

ZnO 

5.4-5.7 

141 

250 

4  -5 

CHABAZITE 

CaAl2(SiO3)4-6H2O 

2.0-2.2 

42 

234 

41-5 

APATITE 

CaF(P04)3 

3.1-3.2 

98 

228 

41 

Gmelinite 

(Na2,Ca)Al2(Si03)4 

•6H2O 

2  .  0-2  .  2 

232 

5 

SMITHSONITE 

ZnC03 

4.3-4.5 

43 

248 

5 

DlOPTASE 

H2CuSiO4 

3.3-3.4 

148 

252 

5  -51 

Eudialite 

Na4Ca3Zr(SiO3)7 

2.9-3.0 

230 

5  -6 

WlLLEMITE 

Zn2Si04 

3.9-4.2 

90 

232 

5  -6 

NEPHELITE 

(K,Na)AlSiO4 

2.5-2.6 

44 

232 

5  -6 

CANCRINITE 

H6Na6Ca(NaCO3)2Al8 

(Si04)9 

2.4-2.5 

91 

230 

5J-61- 

HEMATITE 

Fe203 

4.9-5.3 

134 

218 

6  -61 

Benitoite 

BaTi(SiO3)3 

3.6-3.7 

246 

7 

QUARTZ 

SiO2 

2.65 

55 

262 

7 

Tridymite 

KO, 

2.3 

56 

264 

7-71 

TOURMALINE 

R9Al3(BOH)2(Si06)4 

3.0-3.2 

74 

222 

71-8 

BERYL 

Gl3Al2(SiO3)6 

2.6-2.8 

127 

244 

71-8 

PHENACITE 

Gl2SiO4 

2.9-3.0 

92 

264 

9 

CORUNDUM 

A1203 

3.9-4.1 

45 

260 

AMORPHOUS  OR  CRYSTALLIZATION  UNKNOWN 
Metallic  or  Submetallic  Luster 


1  -3 

WAD 

MnO2,H2O 

3.0-4.3 

17 

208 

2  -21 

PYROLUSITE 

MnO2 

4.7-4.8 

18 

208 

21-3 

PETZITE 

Ag3AuTe2 

8.7-9.0 

14 

206 

3  -5 

WAD 

MnO2,H2O 

3.0-4.3 

17 

208 

3  -31 

Domeykite 

Cu3As 

7.2-7.7 

196 

31 

Whitneyile 

Cu9As 

8.4-8.C 

196 

4 

Algodonite 

Cu«As 

7.6 

196 

274    MINERALS  CLASSIFIED  ACCORDING  TO    CRYSTALLIZATION 


AMORPHOUS    OR  CRYSTALIZATION    UNKNOWN 
Metallic  or  Submetallic  Luster— Concluded 


Hard- 
ness. 

Name. 

Composition. 

Specific 
Gravity. 

Physical 
Tables. 

Blowpipe 
Tables. 

5  -51 
5£-6 
5  -6 
5  -6 

LIMONITK 

TURGITE 

P.SILOMELANE 
WAD 

FeO-OH-«H2O 
FeO-OH,Fe2O3,  H,O 
MnO2,  MnO,  H2O.  etc. 
MnO2,  H2O 

3.6-4.0 
4.2-4.7 
3.7-4.7 
3.0-4.3 

131 
144 
22 
17 

204 
204 
208 
208 

Nonmetallic  Luster 


0  -1 

Saponite 

Mg4Al(OH)2(Si03)5 

•  14H2O 

2.2-2.3 

256 

-2 

GI.AUCONITE 

approx.  KFe(SiO3)2-H2O 

2.2-2.4 

119 

220 

-2 

OZOCEKITE 

CnH2n+2 

0.9-1.0 

128 

212 

-2 

Halloysite 

H4Al2Si2O9-nH2O 

2.0-2.2 

47 

254 

-2} 

Asbolite 

Co.Mn  oxides 

3.1-3.3 

250 

-3 

BAUXITE 

mixture  A1O-  OH  and 

Al(OH), 

2.4-2.6 

47 

256 

-3 

Asphalt 

C.H.O,  etc. 

1.0-1.8 

17 

212 

-4 

GARNIERITE 

approx. 

Hi(Ni,Mg)SttVnH|O 

2.3-2.8 

120 

254 

2 

ROSCOELITE 

H2K(Al,V)3(SiO4)3 

2.9-3.0 

105 

236 

2  -21 

ANTHRACITE  COAI, 

C,  H,  O,  etc. 

1.3-1.7 

19 

212 

2  -21 

BITUMINOUS  COAL 

C,  H,  0,  etc. 

1.2-1.5 

19 

212 

2  -21 

LIGNITE 

C,  H,  O,  etc. 

1.1-1.4 

128 

212 

2  -3 

CHRYSOCOLLA 

approx.  CuSiO3-2II2O 

2.0-2.2 

120 

254 

2  -3 

DEWEYLITE 

H4Mg4(SiO4)r4H2O 

2.0-2.2 

50 

232 

2  -21 

SEPIOLITE 

H4Mg2Si3010 

1.0-2.0 

49 

232 

2  -2| 

Hydrozincilc 

Zn3(OH)4CO3 

3.6-3.8 

49 

248 

2  J-3 

AMBER 

CsoHnOi 

1.0-1.1 

95 

212 

3 

ALLOPHANE 

approx.  Al2SiO5-5H2O 

1.8-1.9 

121 

252 

3 

Zaratite 

Ni3(OH)4CO3-4H2O 

2.6-2.7 

147 

248 

3 

Sussexite 

H(Mn,Mg,Zn)BO3 

3.4 

228 

3  -4 

SERPENTINE 

H4Mg3Si2O9 

2.5-2.6 

'l22 

232 

3  -5 

WAD 

MnOo,  H,O 

3.0-4.3 

17 

250 

4 

Crocidolite 

NaFe'"  (Fe,MK)(SiO3)3 

3.2-3.3 

148 

222 

4-4| 

Bismutite 

BiO-Bi(OH)2CO3 

6.8-7.7 

21G 

4  -41 

Purpuritc 

2(Fe,Mn)PO4-H2O 

3.4 

228 

5-51 

LIMONITE 

FeO-OH-nH2O 

3.6-4.0 

131 

218 

5  -6 

WAD 

MnO2,H2O 

3.0-4.3 

17 

250 

51-6 

TURGITE 

FeO-OH,  Fe2O3,  HoO 

4.2-4.7 

144 

218 

6}-6i 

OPAL 

SiO2-nH2O 

2.1-2.2 

54 

256 

7 

CHALCEDONY 

SiO2 

2.6-2.64 

55 

262 

GLOSSARY 

Acicular.     In  slender,  needle-like  prisms. 

Add  igneous  rocks.    Those  containing  much  silica,  part  of  which 
appears  as  quartz,  if  crystalline. 

Acute.     Sharply  pointed. 

Adamantine  luster.     Like  that  of    cerusite,  diamond,  or  slightly 
oiled  glass. 

Aggregate.     A  group,  cluster,  or  mass. 

Alkaline  taste.     Resembling  the  taste  of  soda. 

Alliaceous  odor.     Garlic-like,  the  odor  of  arsenic  fumes. 

Alluvial.     Deposited  by  streams. 

Amorphous.    Without  crystalline  molecular  structure. 

Amygdaloid.    An  igneous  rock  having  gas  vesicles  filled  with 
secondary  minerals. 

Amygduk.     A  spheroidal  aggregate  of  secondary  minerals  formed 
in  a  vesicle  of  igneous  rock. 

Anhydrous.     Not  containing  hydrogen  or  water  in  its  composition. 

Arborescent.     Branching;  fern-like  or  tree-like;  dendritic. 

Argillaceous.     Consisting  of  or  containing  clay. 

Asterism.    The  property  of  showing  a  six-rayed  star  of  light  on 
polished  faces  in  certain  directions. 

Astringent.     Contracting  or  puckering  the  tissues,  as  the  mouth 
in  astringent  taste. 

Basal.     Parallel  to  the  basal  pinacoid  of  a  crystal;    across  the 
length  of  a  prism. 

Basalt.     Dense,  dark,  heavy,  igneous  rock. 

Basic  igneous  rocks.     Those  low  in  silica;  heavy  and  generally 
dark  colored. 

Bladed.     Having  long  flattened  crystals,  resembling  knife  blades. 

Blebby.     Containing  bubble  cavities,  or  vesicles. 

Botryoidal.     Like  a  bunch  of  grapes;  consisting  of  closely  grouped 
spherical  masses. 

Brittle.     Breaking  or  crumbling  readily  under  a  blow  or  other 
strain ;  opposite  of  tough. 

Capillary.    Hair-like;  very  thin  and  greatly  elongated  prismatic 
crystals. 

275 


276  GLOSSARY 

Cellular.     Full  of  small  openings;  sponge-like. 

Chatoyant.  Possessing  a  changeable  luster,  like  a  cat's  eye  in 
the  dark. 

Clastic.     Composed  of  fragments. 

Cleavabk.  Capable  of  being  split  with  smooth  faces  in  definite 
directions. 

Cleavage.  The  capacity  possessed  by  many  crystalline  minerals 
for  being  split  or  broken  in  certain  definite  directions  with  smooth 
faces.  (See  p.  6.) 

Columnar.     Having  slender  prisms  in  close  parallel  grouping. 

Compact.     Consisting  of  a  firm,  closely  united  aggregate. 

Complex  crystals.     Those  having  many  crystal  forms  and  faces. 

Concentric.  Consisting  of  spherical  layers  about  a  common 
center,  like  an  onion. 

Conchoidal  fracture.     Breaking  with  curved,  shell-like  surfaces. 

Concretion.  A  rounded  or  irregular  mass  that  has  been  formed 
by  the  accumulation  of  dispersed  or  scattered  material. 

Concretionary.  Formed  as  a  concretion;  containing  or  consisting 
of  concretions. 

Confused.     In  irregular,  indistinct  aggregate. 

Conglomerate.  A  rock  composed  chiefly  of  pebbles  cemented 
together. 

Contact  mineral.  One  that  has  been  formed  under  the  influence 
of  igneous  intrusion. 

Contact  Twin.  Two  crystals  of  the  same  mineral  attached  to 
one  another  in  definite  reversed  position. 

Crested.     Consisting  of  groups  of  tabular  crystals  forming  ridges. 

Cruciform.     Forming  a  cross. 

Cryptocrystalline.  Minutely  crystalline;  composed  of  crystal- 
line particles  of  microscopic  dimensions. 

Crystal.  A  crystalline  solid  bounded  by  natural  plane  surfaces. 
(See  pp.  1-6.) 

Crystalline.  Having  symmetrical  molecular  structure  which, 
under  favorable  conditions,  is  expressed  in  the  forms  of  crystals;  in 
the  absence  of  crystals  it  may  be  evidenced  by  cleavage  and  char- 
acteristic optical  properties. 

Crystallization.  The  process  of  forming  crystalline  structure, 
which  may  result  in  crystals  or  in  irregular  crystalline  masses. 

Cubic.  Having  the  form  of  a  cube  (Fig.  5),  as  crystals;  or  the 
directions  of  the  faces  of  a  cube,  as  cubic  cleavage. 

Cyclic.  Circular,  as  in  certain  types  of  repeated  twinning  that 
tend  to  produce  circular  forms. 


GLOSSARY  277 

Decrepitation.  Violent  breaking  away  of  particles,  with  crackling 
sound,  on  sudden  heating.  (See  p.  158.) 

Deflagration.     Sudden  combustion;  flashing  like  gunpowder. 

Dendritic.     Branching;  fern-like  or  tree-like;  arborescent. 

Dense.  Having  a  compact  porcelain-like  texture;  consisting  of 
an  aggregate  of  minute,  indistinguishable  particles. 

Diaphaneity.     Power  of  transmitting  light;  transparency. 

Dichroism.  The  property  of  showing  different  colors  when  viewed 
by  transmitted  light  in  two  directions. 

Dimorphism.  The  occurrence  of  two  minerals  having  the  same 
composition,  but  differing  in  crystallization  and  other  physical 
properties,  and  often  also  in  chemical  properties.  Pleomorphism,  or 
polymorphism,  is  the  broader  term,  referring  to  two  or  more. 

Disseminated.  Scattered  through  a  rock  or  other  mineral  aggre- 
gate in  the  form  of  grains  or  particles. 

Divergent.  Extending  in  different  directions  from  a  point;  ra- 
diating. 

Dodecahedron.  A  crystal  form  in  the  isometric  system  with 
twelve  faces;  the  rhombic  dodecahedron  (Fig.  7). 

Double  refraction.  Separation  of  a  ray  of  light  into  two  parts, 
which  are  refracted  at  different  angles. 

Drusy.  Covered  with  minute  crystals  closely  crowded,  giving  a 
rough  surface  with  many  reflecting  faces. 

Ductile.     Capable  of  being  drawn  into  wire. 

Dull.     Not  reflecting  light;  absence  of  luster. 

Earthy.  Consisting  of  minute  particles  loosely  aggregated;  clay- 
like,  dull. 

Effervescence.     Evolution  of  gas  in  bubbles  from  a  liquid. 

Efflorescence.  A  surface  crust  or  coating,  often  powdery,  formed 
by  evaporation. 

Elastic.  The  property  of  springing  back  to  its  original  form 
when  bent,  as  in  thin  sheets  of  mica. 

Eruptive  rock.  One  formed  by  the  solidification  of  a  surface 
flow  of  lava;  a  volcanic  rock;  sometimes  used  as  a  synonym  of 
igneous  rock. 

Etched.     Having  the  surface  roughened  by  solution  or  corrosion. 

Exfoliation.  Splitting  apart  and  expansion  of  flakes  or  scales  on 
being  heated. 

Felted.     Composed  of  matted  fibers. 

Ferruginous.     Containing  iron. 

Fetid  odor.  A  disagreeable  or  offensive  odor,  as  of  hydrogen 
disulphide. 


278  GLOSSARY 

Fibrous.    Having  thread-like  or  hair-like  form. 

Fissure.    A  crack  or  crevice. 

Flexible.  Capable  of  being  bent  without  breaking,  but  not  re- 
turning to  its  original  position. 

Fluorescence.  The  property  of  showing  colors  by  transmitted 
light  that  are  different  from  the  color  of  the  substance  as  seen  by 
reflected  light. 

Folia.     Thin  flakes  or  leaves;  lamellae. 

Foliated.    Composed  of  or  easily  splitting  into  thin  flakes  or  plates. 

Fossiliferous.     Containing  fossils,  remains  of  plants  or  animals. 

Fracture.  The  form  of  surface  produced  by  breaking  other  than 
by  cleavage  and  parting.  (See  p.  7.) 

Friable.     Readily  broken  into  grains;  crumbling  easily. 

Furrowed.     Having  deep  grooves  or  striations. 

Fusibility.  The  capacity  for  being  fused  or  melted  in  the  blow- 
pipe flame.  (See  p.  157.) 

Gangue.     Minerals  of  little  or  no  value  in  an  ore. 

Globular.     Having  spherical,  or  rounded,  form. 

Gneiss.  A  granite-like  rock  having  more  or  less  definite  parallel 
arrangement  of  its  constituents. 

Granite.  An  igneous  rock  consisting  of  distinguishable  grains  of 
feldspar,  quartz,  and  generally  biotite  or  hornblende. 

Granular.     Composed  of  distinguishable  grains. 

Guano.  An  accumulation  of  excrement  of  sea  birds,  modified  by 
oxidation  and  leaching. 

Habit.  The  form  or  combination  of  forms  commonly  developed 
on  the  crystals  of  a  mineral. 

Hackly  fracture.  Breaking  with  a  rough  surface  having  many 
sharp  points,  like  most  metals. 

Hemimorphic.  Having  the  opposite  ends  (of  crystals)  terminated 
differently,  as  in  Fig.  58. 

Hexagonal.  Six-sided;  the  system  of  crystallization  having  three 
equal  axes  making  angles  of  60°  with  each  other  and  a  fourth 
axis  unequal  and  at  right  angles  to  these.  (Fig.  47-58.) 

Hexoctahedron.  A  form  of  isometric  crystal  having  48  faces. 
(Fig.  4.) 

Hydrous.  Containing  hydrogen  or  water,  and  therefore  yielding 
water  on  heating. 

Hygroscopic.     Capable  of  taking  moisture  from  the  atmosphere. 

Igneous  rock.  A  rock  formed  by  the  solidification  of  a  molten 
magma,  either  at  the  surface,  as  volcanic  lava,  or  within  the  earth, 
as  plutonic  and  intrusive  igneous  rocks. 


GLOSSARY  279 

Ignition.     Heating  with  the  blowpipe  flame. 

Impregnated.  Having  a  substance  intimately  dispersed  or  dis- 
seminated within  it. 

Impressed.     Indented;  marked  bv  pressure. 

Inclusion.     A  foreign  material  inclosed  within  a  mineral. 

Incrustation.     A  crust  or  coating. 

Inelastic.  Not  elastic;  not  returning  to  its  original  form  after 
bending. 

Interlaced.     Confusedly  intertwined,  as  fibers  or  slender  crystals. 

Intermediate  igneous  rocks.  Those  having  neither  very  high  nor 
very  low  silica;  intermediate  between  acid  and  basic  types. 

Intumescence.     The  property  of  swelling  and  bubbling  as  it  fuses. 

Iridescence.  A  play  of  colors,  as  in  a  soap  bubble,  due  to  thin 
surface  film  or  films  of  air  in  minute  crevices. 

Isometric.  The  system  of  crystallization  having  three  equal  and 
interchangeable  axes  at  right  angles  to  each  other.  (Figs.  1-20.) 

Isomorphism.  The  property  possessed  by  some  substances  of 
like  molecular  structure  and  crystallization  of  crystallizing  together 
in  variable  proportions,  forming  homogenous  mixed  crystals.  (See 
p.  11.) 

Lamellae.    Thin  plates  or  layers;  laminae. 

Lamellar.     Consisting  of  lamellae,  or  laminae. 

Laminae.     Thin  plates  or  layers;  lamellae. 

Laminated.     Consisting  of  lamellae,  or  laminae. 

Lava.  Molten  rock  or  the  solid  rock  resulting  from  its  cooling; 
applied  particularly  to  surface  flows. 

Lenticular.  Lens-shaped;  of  tabular  form,  thick  at  the  middle 
and  thinning  toward  the  edges. 

Limestone.  A  rock  composed  chiefly  of  calcium  carbonate  (calcite). 

Lodestone.  Magnetite  that  possesses  natural  polarity,  one  part 
attracting  one  pole  of  a  magnetic  needle,  the  opposite  side  or  end 
attracting  the  other  pole.  Rarely  lodestones  of  pyrrhotite  and  plati- 
num are  found. 

Luster.  The  shine  of  a  mineral  surface,  or  the  manner  in  which 
it  reflects  light.  (See  p.  9.) 

Macroscopic.  Visible  to  the  unaided  eye;  megascopic;  in  con- 
trast with  microscopic. 

Magnetic.  Capable  of  attracting  the  magnetic  needle  or  of  being 
attracted  by  a  magnet. 

Malleable.     Capable  of  being  hammered  or  rolled  into  a  sheet. 

Mammillary.  Having  a  smooth  hummocky  surface,  with  curved 
protuberances  larger  than  botryoidal. 


280  GLOSSARY 

Massive.     Without  crystal  form  or  faces. 

Meager  feel.  Rough  or  harsh  to  the  touch;  the  opposite  of 
smooth  and  greasy  feel. 

Megascopic.  Visible  to  the  unaided  eye;  macroscopic;  in  con- 
trast with  microscopic. 

Metallic  luster.  Having  the  surface  sheen  of  a  metal;  with  a 
metal-like  reflection. 

Metalloidal  luster.     Reflecting  light  somewhat  like  a  metal. 

Metamorphic  rock.  A  rock  (originally  either  igneous  or  sedi- 
mentary) that  has  been  profoundly  changed  under  the  influence  of 
high  temperature  or  great  pressure,  or  both. 

Meteorite.  A  mass  of  stone  or  iron  that  has  fallen  to  the  earth 
from  outer  space. 

Micaceous.  Composed  of  thin  plates  or  scales,  or,  like  mica, 
capable  of  being  easily  split  into  thin  sheets. 

Monoclinic.  The  system  of  crystallization  containing  three 
unequal  axes,  two  at  an  oblique  angle  and  the  third  at  right  angles 
to  these.  (Figs.  38-44.) 

Mottled.     Having  spots  or  irregular  patches,  as  of  color  or  shading. 

Nodular.     Consisting  of  rounded  lumps  or  nodules. 

Nodule.     A  somewhat  irregularly  rounded  mass. 

Nugget.     A  rounded,  irregular  lump  of  native  metal. 

Ocherous.     Earthy,  powdery;  usually  red,  yellow,  or  brown. 

Octahedron.  An  eight-sided  form  in  the  isometric  system  of 
crystallization  (Fig.  1). 

Oolitic.  Containing  or  consisting  of  small  rounded  particles, 
suggesting  fish-roe. 

Opalescence.     A  milky  or  pearly  internal  reflection. 

Opaque.     Incapable  of  transmitting  light. 

Orthorhombic.  The  system  of  crystallization  containing  three 
unequal  axes  at  right  angles  to  one  another.  (Figs.  30-37.) 

Parting.  A  capacity  for  splitting,  much  like  cleavage,  but 
limited  to  certain  definite  planes  of  weakness  (often  due  to  twinning), 
while  true  cleavage  can  be  produced  in  a  given  direction  at  any  point. 

Pearly  luster.    Like  that  of  mother  of  pearl. 

Peat.  The  brown  to  black  partially  decomposed  vegetable 
matter  accumulated  in  swamps. 

Pegmatite.  An  igneous  rock  of  extremely  coarse  texture,  the  most 
common  kind  (granitic)  consisting  chiefly  of  quartz, feldspar, and  mica. 

Penetration  twin.  A  pair  of  crystals  developed  in  reverse  posi- 
tion with  reference  to  one  another  and  each  penetrating  through  the 
other,  (Figs.  12,  32,  33.) 


GLOSSARY  281 

Peridotite.  A  very  basic  igneous  rock,  consisting  chiefly  of 
olivine  and  pyroxenes. 

Phonolite.  A  dense  volcanic  rock  composed  chiefly  of  micro- 
scopic feldspar,  nephelite,  and  pyroxene. 

Phosphorescence.  The  glow  induced  in  some  substances  by  the 
action  of  moderate  heat,  friction,  ultraviolet  light,  or  other  forms  of 
energy,  the  glow  continuing  in  some  cases  a  few  seconds,  or  even 
minutes,  after  the  removal  of  the  cause.  (See  p.  9.) 

Pinacoidal.  Having  crystal  forms  of  two  parallel  planes  which 
are  also  parallel  to  two  or  more  crystallographic  axes,  or  developed 
(as  cleavage  or  parting)  parallel  to  such  a  form. 

Pisolitic.  Composed  of  or  containing  rounded  masses  the  size 
of  peas. 

Pitchy  luster.     Resembling  a  fresh  surface  of  pitch. 

Placer  deposits  (or  placers).  Accumulations  of  sand  and  gravel 
containing  gold  or  other  constituent  of  value. 

Plastic.     Capable  of  being  molded  or  pressed  into  shape. 

Plates.     Broad  flat  tabular  masses,  thicker  than  sheets  or  leaves. 

Platy.     Consisting  of  or  readily  splitting  into  plates. 

Play  of  colors.  Change  of  colors  in  rapid  succession  on  turning 
the  mineral. 

Pleomorphism.     Synonym  of  polymorphism. 

Plumose.     Feather-like. 

Pocket.  An  irregularly  rounded  bunch  or  mass  of  minerals, 
particularly  of  rich  ore,  within  a  rock  or  in  a  local  enlargement  of  a 
fissure. 

Polymorphism.  The  occurrence  of  two  or  more  minerals  having 
the  same  composition  but  differing  in  physical,  and  often  also  in  cer- 
tain chemical,  properties.  Dimorphism  refers  to  groups  of  two, 
trimorphism  to  three,  etc. 

Precipitate.  The  solid  produced  (generally  in  powdery  or 
minutely  crystalline  form)  when  chemical  reaction  produces  an  insol- 
uble compound.  (See  p.  173.) 

Prismatic.  Having  elongation  (of  crystals)  hi  one  direction, 
commonly  parallel  to  one  of  the  crystallographic  axes;  also  parallel 
to  the  faces  of  a  crystal,  as  prismatic  cleavage. 

Pseudohexagonal  (pseudotetragonal,  etc.).  Having  a  false  and 
misleading  resemblance  to  crystals  of  the  hexgonal  (tetragonal,  etc.) 
system. 

Pseudomorph.  A  mineral  aggregate  having  the  form  of  the  crys- 
tal of  another  mineral,  due  to  alteration,  replacement,  etc. 

Pulverulent.    Powdery;  finely  divided,  incoherent  material. 


282  GLOSSARY 

Pungent     Sharp,  prickling,  stinging. 

Pyramidal.  Possessing  the  form  of  or  pertaining  to  the  pyramid, 
a  crystal  form  the  faces  of  which  commonly  intersect  three  crystallo- 
graphic  axes. 

Pyritohedron.  A  form  of  the  isometric  system  of  crystallization 
possessing  twelve  five-sided  faces  (Fig.  18). 

Pyroelectricity.  The  electric  charge  produced  in  certain  minerals 
by  moderate  heat,  so  that  minute  particles  of  paper  or  other  light 
bodies  are  attracted. 

Radiated.  Having  fibers,  columns,  scales,  or  plates  diverging 
from  a  point. 

Rectangular.    Making  right  angles,  or  angles  of  90°. 

Reniform.  Kidney-shaped,  or  having  a  surface  like  a  kidney, 
composed  of  numerous  slightly  curved  surfaces,  the  curved  parts 
much  lower  and  less  prominent  than  in  mammillary. 

Resinous  luster.  Reflecting  light  like  resin,  somewhat  like 
greasy  luster. 

Reticulated.  Having  slender  crystals  or  fibers  crossing  like  the 
meshes  of  a  net. 

Rhombohedral.  Having  the  form  of  the  rhombohedron;  parallel 
to  the  faces  of  such  a  form,  as  rhombohedral  cleavage. 

Rhombohedron.  A  crystal  form  in  the  hexagonal  system  con- 
sisting of  six  faces  intersecting  at  oblique  angles  (Figs.  52-54). 

Roasting.  Heating  at  a  low  red  heat  with  a  strongly  oxidizing 
blowpipe  flame,  for  the  purpose  of  driving  off  sulphur,  arsenic,  etc. 
(See  p.  160.) 

Rosette.    A  cluster  of  flakes  or  scales  resembling  a  rose. 

Saline  taste.     Salty;  resembling  the  taste  of  common  salt. 

Sandstone.     Sedimentary  rock  consisting  of  consolidated  sand. 

Scalenohedron.  A  twelve-sided  crystal  form  in  the  hexagonal 
system,  each  side  being  a  scalene  triangle  (Figs.  55,  56). 

Scaly.     Consisting  of  scales. 

Schiller.     A  bronze-like,  metalloidal  luster. 

Schist.  Metamorphic  rock  with  highly  developed  parallel  or 
foliated  structure,  along  which  it  splits  easily. 

Seam.    A  thin  vein ;  also  a  bed  in  stratified  rocks,  as  a  seam  of  coal. 

Sectile.     Capable  of  being  cut  into  slices,  or  coherent  shavings. 

Selenious  odor.  An  odor  resembling  that  of  horseradish,  or 
decaying  horseradish,  produced  by  heating  some  selenium-bearing 
minerals  in  the  air. 

Shale.  A  laminated  sedimentary  rock  consisting  of  solidified 
mud,  clay,  or  silt. 


GLOSSARY  283 

Silky  luster.  The  luster  of  satin,  due  to  parallel  lustrous 
fibers 

Skeleton  crystals.  Those  with  the  edges  defined,  but  with  faces 
not  fully  filled  in. 

Slate.  Dense  metamorphic  rock  that  splits  readily  into  broad 
thin  sheets. 

Specific  gravity.  The  weight  of  a  substance  compared  with  that 
of  an  equal  volume  of  water.  (See  p.  8.) 

Splendent.    Having  a  brilliant  luster. 

Splintery  fracture.  Breaking  into  elongated,  splinter-like  frag- 
ments. 

Stalactitic.    Having  the  form  of  a  stalactite  or  an  icicle. 

Stalky.     Consisting  of  slender  columns,  or  long  stout  fibers. 

Stellate.     Radiating  so  as  to  produce  star-like  forms. 

Streak.  The  color  of  the  fine  powder,  or  of  the  mark  made  by  a 
mineral  on  a  harder  substance.  (See  p.  9.) 

Striated.     Marked  with  fine  parallel  lines  or  grooves. 

Sublimate.    A  solid  formed  by  the  direct  solidification  of  a  vapor. 

Submetallic  luster.     Like  metallic,  but  somewhat  dulled. 

Syenite.    A  granular  igneous  rock  like  granite,  but  lacking  quartz. 

Tabular.     In  broad  flat  crystals  or  masses. 

Tarnish.  A  thin  surface  film  formed  by  exposure  and  differing 
in  color  from  the  fresh  mineral  within. 

Termination.     The  faces  on  the  end  of  a  crystal. 

Tenacity.    The  degree  or  character  of  cohesion.     (See  p.  8.) 

Tetragonal.  The  system  of  crystallization  having  two  equal  and 
interchangeable  axes  and  a  third,  shorter  or  longer,  at  right  angles 
to  these.  (Figs.  21-29.) 

Tetrahedron.  A  four-sided  form  in  the  isometric  system  of 
crystallization,  each  side  of  which  is  an  equilateral  triangle  (Fig.  13). 

Tough.     Difficult  to  break;  the  opposite  of  brittle. 

Translucent.  Transmitting  some  light,  but  objects  are  not  seen 
clearly  through  such  a  substance. 

Transparency.     The  quality  of  transmitting  light;  diaphaneity. 

Transparent.  Transmitting  light  freely,  so  that  objects  may  be 
seen  clearly. 

Trap  rock.  A  dark,  basic,  heavy  igneous  rock,  fine  grained  or 
dense  in  texture. 

Triclinic.  The  system  of  crystallization  having  three  unequal 
axes  intersecting  each  other  at  oblique  angles.  (Figs.  45,  46.) 

Trilling.  A  symmetrical  attachment  or  intergrowth  of  three 
crystals. 


284  GLOSSARY 

Trimorphism.     See  Polymorphism. 

Twin.  A  symmetrical  combination  or  intergrowth  of  two  crys- 
tals. (See  Figs.  12,  29,  32, 33,  39.) 

Unctuous  feel.     Very  smooth  and  slippery;  greasy  to  the  touch. 

Variegated.     Having  different  colors. 

Vein.  A  crack,  crevice,  or  fissure  filled,  or  partially  filled,  with 
mineral  matter. 

Vesicular.  Having  steam  or  gas  bubble  cavities,  as  some  igneous 
rocks. 

Vitreous  luster.    Like  that  of  a  surface  of  broken  glass. 

Warty.    Having  small  rounded  protuberances,  like  warts. 

Zonal.    Arranged  in  zones,  belts,  or  layers. 


ABBREVIATIONS 


abund. 

abundant 

mall. 

malleable 

acic. 

acicular 

mammil. 

mammillary 

adamant. 

adamantine 

mm. 

millimeter  (1-25  inch) 

alk. 

alkaline 

mag. 

magnetic 

am. 

ammonia 

mass. 

masses,  massive 

am.mol. 

ammonium  molybdate 

micac. 

micaceous 

amorph. 

amorphous 

mon. 

monoclinic 

ami. 

amount 

non-mag. 

non-m  agnetic 

anhydr. 

anhydrous 

non-vol. 

nonvolatile 

at.  wt. 

atomic  weight 

oct. 

octahedral 

b.b. 

before  the  blowpipe 

o.f. 

oxidizing  flame 

bd. 

bead 

opaq. 

opaque 

blk.,  blkh. 

black,  blackish 

orth. 

orthorhombic 

bot.,  bo  try. 

botryoidal 

o.t. 

open  tube 

bp. 

blowpipe 

P.I,  P.  2,  etc. 

parting  in  1,  2,  etc, 

,,  direc- 

brn.,  brim. 

brown,  brownish 

P.,  part. 

parting 

[tiona 

C.l,C.2.,etc, 

,  cleavage  in  1,  2,  etc.,  direc- 

per. 

perfect 

capil. 

capillary                         [tions 

phys. 

physical 

ch. 

charcoal 

pinac. 

pinacoidal 

cleav. 

cleavage 

PPt. 

precipitate 

col. 

color,  colored 

prism. 

prismatic 

cols. 

colorless 

pseudm. 

pseudomorphic 

colum. 

columnar 

pyrito. 

pyritohedral 

comp. 

compact 

pyram. 

pyramidal 

cone. 

concentrated 

rad. 

radial,  radiating 

conch. 

conchoidal 

rdh. 

reddish 

cp. 

compare 

reac. 

reacts,  reaction 

c.t. 

closed  tube 

res. 

residue,  resinous 

decrep. 

decrepitates,  decrepitation 

r.f. 

reducing  flame 

dif. 

difficulty 

rhom. 

rhombohedral 

dil. 

dilute 

sil. 

silica  (SiO2) 

direc. 

direction 

sol. 

soluble,  solution 

dissem. 

disseminated 

somet. 

sometimes 

disting. 

distinguished 

sp.gr.,  G.      . 

specific  gravity 

dk. 

dark 

s.ph. 

sodium  metaphosphate 

dodec. 

dodecahedral 

splint. 

splintery 

duct. 

ductile 

St. 

streak 

efferv. 

effervescence 

stalac. 

stalactitic 

efflores. 

efflorescence 

subl. 

sublimate 

F.,  fract. 

fracture 

submet. 

submetallic 

fibr. 

fibrous 

tab. 

tabular 

flex. 

flexible 

tar. 

tarnishes,  tarnish 

fol. 

foliated 

temp. 

temperature 

fus. 

fuses,  fusibility 

tetr. 

tetragonal 

G.,  sp.gr. 

specific  gravity 

tetrh. 

tetrahedral 

gel. 

gelatinous 

transp. 

transparent 

gran. 

granular 

transl. 

translucent 

grn.,  grnh. 

green,  greenish 

tri. 

triclinic 

gry.,  gryh. 

gray,  grayish 

us. 

usually 

*•' 

H. 

hardness 

vesic. 

vesicular 

hemimor.  ' 

hemimorphic 

vitr. 

vitreous 

hex. 

hexagonal 

vol. 

volatilizes,  volatile 

ign. 

ignition 

w. 

with 

incrust. 

incrusting 

wh.,  whh. 

white,  whitish 

intumes. 

intumescence 

xl.,  xls. 

crystal,  crystals 

iso. 

isometric,  isomorphic 

xln. 

crystalline 

lamel. 

lamellar 

yel.,  yelh. 

yellow,  yellowish 

It. 

light 

285 


CHEMICAL  ELEMENTS 


Sym- 
bol. 

Element. 

Atomic 
Weight. 

Sym- 
bol. 

Element. 

Atomic 
Weight. 

^ 

39  9 

Mo 

96  0 

Ag 
Al 

Silver  (Argentum)  
Aluminum  

107.88 
27.1 

N 

Na 

Nitrogen  
Sodium  (Natrium)  

14.008 
23  00 

As 

Arsenic  

74.96 

Nb 

Niobium,  see  Columbium 

Au 
B 

Gold  (Aurum)  
Boron  

197.2 
10.9 

Nd 

Ne 

Neodymium  
Neon  

144.3 
20  2 

Ba 

Barium   

137.37 

Ni 

Nickel  

58  68 

Be 

Beryllium,  see  Glucinum 

Nt 

Niton  

222  4 

Bi 

208.0 

o 

Oxygen     

16  000 

Br 

79  92 

Os 

Osmium    . 

190  9 

c 

Carbon                    

12  005 

p 

31  04 

Ca 

40  07 

Pb 

207  20 

Cb 

93  1 

Pd 

106  7 

Cd 

112  40 

Pr 

140  9 

Ce 

Cerium 

140  25 

Pt 

195  2 

Cl 

Chlorine  

35.46 

Ra 

Radium  

226  0 

Co 

Cobalt  

58.97 

Rb 

Rubidium  

85  45 

Cr 

Chromium  

52.0 

Rh 

Rhodium  

102  9 

Cs 

Caesium  

132  81 

Ru 

Ruthenium         

101  7 

Cu 

Copper  (Cuprum)   

63  57 

s 

Sulphur            .    .    .    ... 

32  06 

Dy 

Dysprosium  

162  5 

Sa 

150  4 

Er 

Eu 
F 

Erbium  
Europium  
Fluorine              

167.7 
152.0 
19  0 

Sb 
Sc 
Se 

Antimony  (Stibium)  
Scandium  

120.2 
44.1 
79  2 

Fe 

55  84 

Si 

28  3 

Ga 

70  1 

Sn 

Tin  (Stannum) 

118  7 

Gd 

157  3 

Sr 

87  63 

Ge 

72  5 

Ta 

Tantalum 

181  5 

Gl 

Glucinum  

9.1 

Tb 

Terbium  

159.2 

H 

Hydrogen  

1.008 

Te 

Tellurium  

127  5 

He 

Helium  

4.00 

Th 

Thorium   

232.15 

Hg 

Mercury  (Hydrargyrum). 

200.6 

Ti 

Titanium  

48  1 

Ho 

Holmium  

163  5 

Tl 

Thallium          

204.0 

I 

Iodine  

126  92 

Tm 

Thulium       

168  5 

In 

Indium  

114  8 

u 

238  2 

Ir 
K 
Kr 

Iridium  
Potassium  (Kalium)  
Krypton     

193.1 
39.10 
82  92 

V 

w 

Xe 

Vanadium  
Tungsten  (Wolframium)  . 

51.0 

184.0 
130  2 

La 

Lanthanum  

139  0 

Y 

Yttrium      

89  3 

Li 

Lithium     

6  94 

Yb 

173  5 

Lu 

Lutecium  

175  0 

Zn 

Zinc                 

65  37 

Mg 

Magnesium  

24  32 

Zr 

90  6 

Mn 

Manganese       

54  93 

286 


INDEX 


NOTE. — A  dash  ( — )  separates  references  to  the  physical  tables  from  those  to  the  blowpipe 
tables.     Mineral  names  are  printed  in  heavy-faced  type. 


Abbreviations,  285 

Achroite,  74 

Acids,  155,  170 

Acmite,  63 

Actinolite,  110—238 

Adamantine  spar,  57 

Adularia,  37 

Aegirine,  63 

Aegirite,  63,  84,  113—222,  240 

Agalmatolite,  256 

Agate,  55 

mortar,  154 
Aggregates,  crystal,  6 
Agolite,  29 
Alabandite,  148—202 
Alabaster,  30 
Albite,  37,  63—238 
Alexandrite,  114 
Algodonite,  196 
Allanite,  71—206,  220,  232 
Allophane,  50,  96,  121—252 
Allotropy,  11 
Almandine,  101,  127 
Almandite,  101—244 
Altaite,  15,  24,  28—206 
Alum  stone,  52 
Aluminum,  tests  for,  174 
Alunite,  52,  97—248,  256 
Alunogen,  250 
Amalgam,  28 — 202 
Amazonstone,  37 
Amazonite,  37 
Amber,  50,  95—212 
Amber  mica,  106 
Amblygonite,  37,  84,  112—242 
Amethyst,  55 
Ammonia,  155,  173 
Ammonium  carbonate,  156,  173 

hydroxide,  155,  173 

molybdate,  156 

oxalate,  156 

sulphide,  173 


Amorphous  minerals,  1,  274 
Amosite,  148 
Amphibole  asbestos,  47 
Amphibole  group: 

Actinolite,  110—238 

Anthophyllite,  36,  62,  82,  110—222, 
238,   258 

Asbestos,  47 

Glaucophane,  64,  112—238 

Hornblende,  61,  82,  110,    131,    143, 
148—222, 238 

Nephrite,  54 

Tremolite,  36,  62,  82—238 
Amphigene,  54 
Analcime,  53 

Analcite,  53,  98,  123—232 
Anatase,  68 

Andalusite,  38,  64,  85,  113—260 
Andesine,  37,  63—238 
Andradite,  102—220,  244 
Anglesite,  40,  65,  87,  115—214 
Anhydrite,  40,  65,  87—226 
Anhydrous  gypsum,  40 
Ankerite,  40,  66,  87,  115—246 
Annabergite,  120,  146—218 
Anorthite,  37,  63—232,  238 
Anorthoclase,  37 
Anthophyllite,   36,   62,  82,    110—222, 

238, 258 

Anthracite  Coal,  19—212 
Antimonial  silver,  28 
Antimonite,  18 
Antimony,  28—198 

glance,  18 

tests  for,  174 
Anvil,  153 

Apatite,  52,  98,  123—228,  250 
Apophyllite,  33,  79,  107—234 
Apparatus,  151 
Aqua  fortis,  155 
Aquamarine,  127 
Aqua  regia,  155 
287 


288 


INDEX 


Aragonite,  41,  66,  87,  115—246 
Arfvedsonite,  222 
Argentite,  17,  18—200 
Arkansite,  72 
Arsenic,  28—196 

bloom,  49 

tests  for,  175 
Arsenolite,  212 
Arsenical  pyrites,  16 
Arsenopyrite,  16 — 196 
Asbestos,   36,  47,  51,  62,  70,  82,  96, 
110,  122,  145,  148—222,  238,  258 
Asbolan,  17 
Asbolite,  250 
Asparagus  stone,  98 
Asphalt,  17,  128,  136—212 
Asphaltum,  17 
Asterism,  8 
Atacamite,  147—214 
Augite,  62,  67,  83,  89,  111,  132,  143, 

149—222,  240 
Aurichalcite,  248 
Autunite,  138 — 228 
Aventurine,  55 

feldspar,  37 

Axinite,  33,  60,  80,  108—242 
Azurite,  147—214 

Balas  ruby,  127 
Barite,  39,  86,  115—226 
Barium  chloride,  156,  173 

hydroxide,  156 

tests  for,  175 
Barytes,  39 
Barytocalcite,  246 
Basanite,  56 
Bases  in  silicates,  185 
Bauxite,  46,  47,  92—256 
Bead  tests,  168,  171 
Beauxite,  47 

Beaverite,  135—214,  216 
Bellmetal  ore,  15 
Benitoite,  246 
Bentonite,  47 

Beryl,  57,  103,  127—244,  260 
Biotite,  68,  76,  106—204,  220,  236 
Bismuth,  27—202 

glance,  14 

tests  for,  175 
Bismuthine,  14 
Bismuthinite,  14,  18—202 


Bismutite,  216 

Bituminous  Coal,  19,  128—212 

Black  band  ore,  41 

Black  copper,  21 

Black  diamond,  45 

Black  hematite,  22 

Black  jack,  88 

Black  lead,  17 

Black  mica,  58 

Black  oxide  of  copper,  21 

Black  silver,  18 

Blast,  156 

Blende,  88 

Bloodstone,  55 

Blowpipe,  151 

determination  by,  151,  191 

operations,  156 

tables,  191,  194 
Blue  asbestos,  148 
Blue  carbonate  of  copper,  147 
Blue  copper,  147 
Blue  glass,  154 
Blue  iron  earth,  104 
Blue  John,  116 
Blue  spar,  124 
Blue  vitriol,  121 
Bluestone,  121 
Bog  iron  ore,  131 
Bog  manganese,  17 
Boracite,  56,  102,  126—228,  242 
Borax,  30,  58,  105—226,  228 
Borax,  154 

bead,  168,  169 

glass,  154 
Boric  acid,  29 
Boraite,  24—200 
Boron,  tests  for,  176 
Boronatrocalcite,  46 
Bort,  45 
Botryolite,  53 
Bournonite,  20 — 198 
Braunite,  16,  23,  26,  134—208 
Breunnerite,  42,  88—248 
Brimstone,  94 
Brittle  mica,  32 
Brittle  silver,  18 
Brochantite,  147—216 
Bromargyrite,  95 
Bromine,  tests  for,  176 
Bromyrite,  95,  121,  138—216 
Bronze  mica,  106 


INDEX 


289 


Bronzite,  36 

Brookite,  72,  99—210,  262 
Brown  clay  ironstone,  131 
Brown  coal,  128 
Brown  hematite,  131 
Brown  ocher,  131 
Brown  spar,  248 
Brucite,  30,  105—248,  252 
Brush,  charcoal,  154 
Burners,  151,  152 
Bytownite,  37,  63—238 

Cadmium,  tests  for,  176 

blende,  140 
Cairngorm,  55 
Calamine,  35,  43,  53,  81,  89,  98,  109, 

117,  123—252 

Calaverite,  24,  27,  138—206 
Calc  sinter,  40 
Calc  spar,  40 
Calc  tufa,  40 
Calcareous  marl,  40 
Calcite,  40,  65,  86,  115—246 
Calcium,  tests  for,  176 
Californite,  101 
Calomel,  47,  70,  93—212 
Cancrinite,  44,  68,  91,  117—230 
Cannel  coal,  19 
Capillary  pyrites,  24 
Carbon,  45 

tests  for,  177 
Carbonado,  45 
Carnallite,  47,  93—224 
Carnelian,  55 
Carnotite,  135—228 
Cassiterite,  55,  73,  100,  135,  145—262 
Cat  gold,  75 
Cat's  eye,  55 
Caustic  potash,  156 
Celestite,  40,  87,  115—226 
Cerargyrite,  46,  69,  93,  119—216 
Cerusite,  51,  70,  96—214 
Ceylonite,  127 
Chabazite,  42,  89—234 
Chalcanthite,  121—216 
Chalcedony,  55,  74,  102,  126—262 
Chalcocite,  17,  19—200 
Chalcophyllite,  216 
Chalcopyrite,  24 — 200 
Chalcotrichite,  141 
Chalk,  40 


Chalybite,  41 
Change  of  color,  8 
Charcoal,  153 

brush,  154 
Chemical  determination,  151,  191 

elements,  286 

properties,  10 

reagents,  154 

tests,  156 
Chert,  55 
Chessylite,  147 
Chiastolite,  38 
Chile  saltpeter,  48 
China  clay,  47 
Chloanthite,  16—196 
Chlorine,  tests  for,  177 
Chlorite,  104,  145—236,  254 
Chloritoid,  60,  108,  149—222,  258,  260 
Chlorospinel,  127 — 262 
Chondrodite,  54,  100—252 
Chrome  chlorite,  75 

garnet,  244 

spinel,  262 
Chromic  iron,  133 

Chromite,  133,  144—208,  210,  258,  262 
Chromium,  tests  for,  178 
Chrysoberyl,  38,  85,  114—260 
Chrysocolla,  120,  146—254 
Chrysolite,  85 
Chrysoprase,  55 
Chrysotile,  47 

Cinnabar,  135,  137—202,  212 
Cinnamon  stone,  102 
Citrine,  55 
Classification,  physical,  13 

crystallographic,  266 
Clay  ironstone,  41 
Cleavage,  6 
Cleiophane,  88 
Clinochlore,  104 
Closed  tube,  153,  165 

sublimates  in,  166 
Cobalt,  bloom,  137 

glance,  15 

nitrate,  156,  173 

ocher,  137 

pyrites,  15 

tests  for,  178 
Cobaltite,  15,  25—196 
Cockscomb  pyrites,  26 
Cogwheel  ore,  20 


290 


INDEX 


Coking  coal,  19 

Colemanite,  34—228 

Color,  8 

Color  screens,  160 

Columbite,  23,  134—204,  210,  242 

Columbium,  tests  for,  178 

Common  mica,  30 

Common  salt,  39 

Composition,  10 

Contact  twins,  2 

Cookeite,  236 

Copiapite,  76,  105,  137—218 

Copper,  138—202 

glance,  19 

nickel,  25 

pyrites,  24 

tests  for,  179 

vitriol,  121 
Copperas,  120 

Cordierite,  60,  80, 108—244,  260 
Corundum,  45,  57,  69,  75,  92,  103,  118, 

127—260 
Covelline,  17 
Covellite,  17—200 
Crocidolite,  47,  145,  148—222 
Crocoite,  139—214 
Crucible,  porcelain,  154 
Cryolite,  49,  95—226 
Crystal,  definition  of,  1 


tables,  266 
Crystallization,  1 
Culsageeite,  75 
Cuprite,  130,  141—204,  214 
Cuprodescloizite,  140 
Cuproscheelite,  89 
Cyanite,  35,  37,  42,  44,  61,  64,  66,  68, 

109, 113, 116,  118—256,  260 
Cymophane,  114 


Damourite,  30 
Danalite,  220,  230 
Danburite,  56,  103—242 
Dark  ruby  silver,  129 
Datolite,  53,  99,  123—230 
Decrepitation,  158 
Definition  of  mineral,  1 
Descloizite,  129,  140—214 
Descriptions  of  minerals,  14 
Desmine,  32 


Determination  by  blowpipe,  151,  191 

by  crystallization,  266 

by  physical  properties,  12 
Determinative  tables,  12,  194,  266 
Deweylite,  50,  95,  121—232,  254 
Diallage,  62 
Dialogite,  88 
Diamond,  45,  69,  92,  118—264 

mortar,  154 
Diaphaneity,  9 

Diaspore,  33,  60,  79,  108—260 
Diatomaceous  earth,  46 
Diatomite,  46 
Dichroite,  108 
Dimethylglyoxime,  156 
Dimorphism,  11 

Diopside,  36,  43,  62,  67,  111—240 
Dioptase,  148—252 
Disthene,  109,  113 
Dogtooth  spar,  40 
Dolomite,  40,  66,  87,  115—246 
Domeykite,  196 
Dry  bone,  43 
Dyscrasite,  28—198 
Dufrenite,  218 

Earthy  cobalt,  17 
Elaeolite,  44 
Electric  calamine,  35 
Electrum,  139—202 
Elements,  table  of,  286 

tests  for,  174 
Embolite,  93,  119—216 
Emerald,  127 

copper,  148 

nickel,  147 
Emery,  45 
Enargite,  20—196 
Endellionite,  20 

Enstatite,  36,  43,  83,  90,  111—240,  258 
Epidote,  60,  79,  107—222,  246 
Epsom  salt,  49 
Epsomite,  46,  49—224 
Erubescite,  24 
Erythrite,  137—218 
Essonite,  102 
Eucolite,  230 
Eudialite,  230 

False  topaz,  55 

Fayalite,  85,  101,  113,  125—220 


INDEX 


291 


Feather  ore,  14 

Feel,  10 

Felspar  group: 

Albite,  37,  63—238 
Andesine,  37,  63,— 238 
Anorthite,  37,  63—232,  238 
Bytownite,  37,  63 — 238 
Labradorite,  37,  63—234,  238 
Microcline,  37—238 
Oligoclase,  37,  63—238 
Orthoclase,  37,  63,  84,  112—238 

Ferberite,  21,  25,  131,  142—204,  222 

Fergusonite,  72,   100,   133,   144—210, 
264 

Ferromagnesian  mica,  58 

Ferruginous  quartz,  55 

Fibrolite,  33 

Filter  paper,  154 

Fire  opal,  54 

Flame,  blowpipe,  156,  157 

Flame  colors,  160,  161 

Flame-color  screens,  160 

Flint,  55 

Flos  ferri,  41 

Fluorescence,  9 

Fluorine,  tests  for,  179 

Fluorite,  42,  89,  116—226 

Fluor  spar,  116 

Fontainebleau  limestone,  40 

Fool's  gold,  26 

Forceps,  or  tweezers,  152,  153 

Forsterite,  85,  101,  113,  125—252 

Fowlerite,  83 

Fracture,  7 

Franklinite,  23,  134—208 

Freibergite,  21,  129—198 

French  chalk,  29 

Fuller's  earth,  47 

Funnel,  glass,  154 

Fusibility,  scale  of,  159 

Fusion,  157,  158 

Gadolinite,  73, 101,  125,  150—232,  252 
Gahnite,  127 — 262 
Galena,  19—200 
Galenite,  19 
Garnet  group : 

Almandite,  101—244 

Andradite,  102—220,  244 

Grossularite,  45,  55,  102—244 

Pyrope,  101—244 


Garnet  group: — Continued 

Schorlomite,  102—232 

Spessartite,  102—240,  244 

Uvarovite,  102—244,  262 
Garnierite,  120,  122,  146—254,  258 
Gay-Lussite,  224,  226 
Gedrite,  62 
Genthite,  120 
Gersdorffite,  15 — 196 
Geyserite,  54 

Gibbsite,  50,  78,  106—256 
Glass  funnel,  154 
Glauberite,  31,  77—226 
Glauber  salt,  48 
Glaucodot,  196 

Glauconite,  69,  119,  145—220 
Glaucophane,  64,  112—238 
Glossary,  275 
Gmelinite,  232,  234 
Goethite,  131,  135,  142—204,  208,  218, 

250 
Gold,  139—202 

tests  for,  179' 
Golden  beryl,  127 
Goslarite,  250 
Grammatite,  36 
Graphic  tellurium,  26 
Graphite,  17—210 
Gray  antimony,  18 
Gray  copper,  21 
Green  carbonate  of  copper,  147 
Green  copper,  147 
Green  earth,  119 
Green  glass,  154 
Green  lead  ore,  122 
Green  vitriol,  120 
Greenockite,  135,  140—250 
Greensand,  119 
Grossular,  102 

Grossularite,  45,  55,  102—244 
Gymnite,  50 
Gypsite,  30,  46 

Gypsum,  30,  39,  58,  64,  76,  85—224, 
226 

Hair  pyrites,  24 
Halite,  39,  65,  86,  114—224 
Hard  coal,  19 
Halloysite,  47—254 
Hammer,  mineralogical,  153 
Hanksite,  224 


292 


INDEX 


Hardness,  7 

Hannotome,  34,  81—132,  244 

Hausmannite,  131,  143 — 208,  250 

Hauyne,  230 

Hauynite,  230 

Heavy  spar,  39 

Hedenbergite,  62,  67,  83,  89,  111,  132, 

143,  149—220,  240 
Heliotrope,  55 
Hematite,  134,    135,    144—204,    208, 

218,  250 

Hemimorphite,  35 
Hercynite,  127 — 262 
Herderite,  228,  244 
Hessite,  14,  20,  27—206 
Hessonite,  102 
Heulandite,  32,  78—234 
Hexagonal  system,  2,  5,  6,  272 
Hiddenite,  38 
Hornblende,  61,  82,  110,  131,  143,  148 

—222,  238 
Horn  quicksilver,  47 
Horn  silver,  46 
Hornstone,  55 
Horseflesh  ore,  24 

Huebnerite,  21,  25,  131,  142—234,  242 
Hyacinth,  57 
Hyalite,  54 
Hyalophane,  37 
Hydrargillite,  50 
Hydrochloric  acid,  155,  173 
Hydrocuprite,  141 
Hydrogen,  peroxide,  156 

tests  for  ,  180 
Hydrohematite,  144 
Hydromagnesite,  248 
Hydrozincite,  49,  94—248 
Hypersthene,  59,  67,  79,  91,  107,  111, 

132,  143—222,  258 

Iceland  spar,  40 
Idocrase,  101 
Ignition,  157,  160 
on  charcoal,  160 
Dmenite,  22,  132—206,  210 
Hvaite,  22—206,  220 
Indicolite,  74 
Indigo  copper,  17 
Infusorial  earth,  46 
Instructions  and  precautions,  12 
lodargyrite,  136 


Iodide  sublimates,  164 
Iodine,  tests  for,  180 
lodyrite,  136—216 
lolite,  108 
Iridescence,  9 
Iridium,  29—210 

tests  for  180,  184 
Iridosmine,  29 
Iridosmium,  29 — 210 

tests  for,  184 
Iron,  206 

pyrites,  26 

spinel,  262 

tests  for,  180 
Isinglass,  30 
Isomerism,  11 

Isometric  system,  1,  2,  3,  266 
Isomorphism,  11 

Jack,  88 

Jade,  36,  54,  62,  82,  125—238,  240 

Jadeite,  54 

Jamesonite,  14,  19—198 

Jargon,  57 

Jarosite,  218 

Jasper,  56 

Jaspopal,  54 

Jefferisite,  75 

Jeffersonite,  240 

Jet,  18 


Kainite,  39,  86—224 
Kalinite,  224,  248,  250 
Kaemmererite,  75 — 236,  254 
Kaolin,  47 

Kaolinite,  46,  47,  92,  93—256 
Kermesite,  212 
Kidney  ore,  134 
Krennerite,  14,  24,  27—206 
Kunzite,  38 
Kyanite,  109,  113 

Laboratory  records,  192 
Labradorite,  37,  63—234,  238 
Lamps,  151,  152 
Lapis  lazuli,  148 
Laumontite,  41,  88—230 
Lawsonite,  38,  114—244 
Lazulite,  124—256 
Lazurite,  148—230 


INDEX 


293 


Lead,  glance,  19 

tests  for,  181 

vitriol,  40 

Leadhillite,  31,  77,  106—214 
Lepidocrocite,  142 
Lepidolite,  31,  77,  106—236 
Lepidomelane,  220,  236 
Leucite,  54,  71,  99—254 
Leucopyrite,  15 
Lievrite,  22 
Light  ruby  silver,  137 
Light  filters,  160 
Lignite,  18,  128,  138—212 
Lime  feldspar,  232,  238 
Lime-soda  feldspar,  37 
Limestone,  246 
Limonite,    131,    135,    142—204,    208, 

218,  250 

Linnaeite,  15—202 
Lithia  mica,  31 
Lithium,  tests  for,  181 
Lithiophilite,  228 
Lodestone,  23 
Loellingite,  15—196 
Luster,  9 

Made,  38 

Magnesia  mica,  106 
Magnesite,  42,  88—248 
Magnesium,  tests  for,  181 
Magnet,  154 
Magnetic  iron  ore,  22 
Magnetic  pyrites,  25 
Magnetism,  10 
Magnetite,  22—204,  206 
Malachite,  147—214 
Malacolite,  36 
Manganese,  blende,  148 

glance,  148 

tests  for,  182 
Manganite,  21,  130—208 
Marble,  246 
Marcasite,  16,  26—200 
Margarite,  32,  59,  78—236,  256 
Marl,  calcareous,  40 

greensand,  119 
Marmolite,  122 

Martite,  134,  144—204,  208,  218 
Meerschaum,  49 
Melaconite,  17,  21—204 
Melanite,  102 


Melanterite,  48,  94,  120—218 

Melilite,  232 

Menaccanite,  22 

Mercury,  26 — 202 
blende,  137 
tests  for,  182 

Merwin's  flame-color  screen,  154 

Mesolite,  230 

Mica  group: 

Biotite,  58,  76,  106—204,  220,  236 
Cookeite,  236 

Lepidolite,  31,  77,  106—236 
Lepidomelane,  220,  236 
Muscovite,  30,  58,  76,  105—236 
Paragonite,  31,  59,  76,  106—236 
Phlogopite,  31,  59,  77,  106—204, 236 

Microcline,  37 — 238 

Microcosmic  salt,  155 

Microlite,  258 

Microperthite,  37 

Milk  opal,  54 

Milky  quartz,  55 

Millerite,  24—202 

Mimetite,  51,  97—214 

Mineral,  definition  of,  1 

Mineral  pitch,  17 

Mineral  wax,  128 

Mirabilite,  48—224 

Mispickel,  16 

Misy,  76 

Mixed  crystals,  11 

Molybdenite,  17—210 

Molybdenum,  tests  for,  182 

Molybdic  ocher,  92 

Molybdite,  92,  126—228 

Monazite,  99,  124—256 

Monoclinic  system,  2,  4,  5,  270 

Moonstone,  37 

Morganite,  127 

Mortars,  154 


Mountain  cork,  47 

leather,  47 

paper,  47 

wood,  47 
Mundic,  25 

Muriatic  acid,  155,  173 
Muscovite,  30,  58,  76,  105—236 

Nagyagite,  206 
Nail  head  spar,  40 


294 


INDEX 


Native  antimony,  28 

arsenic,  28 

bismuth,  27 

boric  acid,  29 

copper,  138 

gold,  139 

iridium,  29 

iron,  206 

mercury,  26 

paraffin,  128 

platinum,  29 

silver,  27 

sulphur,  94 

tellurium,  27 

ultramarine,  148 

vermilion,  137 
Natrolite,  35,  82—230 
Natron,  224 
Natroborocalcite,  46 
Needle  zeolite,  35 
Nemalite,  30 
Nepheline,  44 

Nephelite,  44,  67,  90,  117—232 
Nephrite,  54 
Niccolite,  25,  143—196 
Nickel,  bloom,  120 

green,  120 

ocher,  120 

pyrites,  24 

tests  for,  183 
Nigrine,  72 

Niobium,  see  Columbium 
Niter,  48—226 
Nitric  acid,  155 
Nitrocalcite,  226 
Nitrogen,  tests  for,  183 
Nitrohydrochloric  acid,  155 
Nosean,  230 
Noselite,  230 
Noumeite,  120 

Ocher,  brown,  131 

red,  144 

yellow,  142 

Octahedrite,  68,  91,  118—210, 
Odor,  10 
Oil  of  vitriol,  155 
Oligoclase,  37,  63—238 
Olivenite,  139,  146—216 
Olivine,  85,  101,  113,  125—252 
Onyx,  56 


Opal,  54,  72,  100,  124—256,  260,  264 

Opal  agate,  54 

Opalescence,  8 

Open  tube,  153,  165,  166 

sublimates  in,  167 
Ophicalcite,  122 
Orangeite,  130 
Orpiment,  136—212 
Orthite,  71 

Orthoclase,  37,  63,  84,  112—238 
Orthorhombic  system,  2,  4,  268 
Osmiridium,  29 
Osmium,  tests  for,  183,  184 
Ottrelite,  60,  108,  149—222,  258,  260 
Ozocerite,  70,  93,  119,  128,  136—212 
Oxidizing  flame,  157 
Oxygen,  tests  for,  183 

Palladium,  tests  for,  183,  184 

Pandermite,  34 

Paraffin,  native,  128 

Paragonite,  31,  59,  76,  106—236 

Parting,  6 

Peacock  copper,  24 

Pearceite,  20—196 

Pearl  spar,  40 

Pectolite,  52,  98—234 

Pencil  stone,  29 

Penetration  twins,  2 

Pennine,  104 

Pentlandite,  25—202 

Peridot,  85 

Perofskite,  91 

Perovskite,  68,  91—210,  258 

Perthite,  37 

Petalite,  242 

Petzite,  14,  20,  28—206 

Pharmacolite,  49,  70,  95,  120—228 

Phenacite,  45,  92—264 

Phillipsite,  34,  81—232 

Phlogopite,  31,  59,  77,  106—204,  236 

Phosphate  nodules,  98 

rock,  98 
Phosphorite,  98 
Physical  classification,  13 

properties,  6 

tables,  12 
Phosphorescence,  9 
Phosphorus,  tests  for,  184 

salt,  155 

bead,  168,  171  _-«  ^ 


INDEX 


295 


Picrolite,  122 

Picotite,  127—262 

Piedmontite,  242 

Finite,  30 

Pistacite,  79 

Pitchblende,  22 

Plagioclase  feldspars,  37—238 

Plasma,  55 

Plaster  tablets,  154 

sublimates  on,  164 
Platiniridium,  29 
Platinum,  29—210 

tests  for,  184 

wire,  153 
Play  of  colors,  8 
Pleomorphism,  11 
Pleonaste,  127—262 
Plumbago,  17 
Polybasite,  19,  23—198 
Polycrase,  264 
Polyhalite,  32,  78,  139—226 
Polymorphism,  11 
Porcelain  clay,  47 
Porcelain  crucible,  154 
Potash  alum,  224 

feldspar,  37 

mica,  30 
Potassium  bisulphate,  155 

ferricyanide,  156 

ferrocyanide,  156 

hydroxide,  156 

nitrate,  155 

tests  for,  184 
Potstone,  29 
Precautions,  12,  191 
Precious  opal,  54 
Precipitates,  173 
Prehnite,  54,  72,  125—234,  244 
Priceite,  34 
Prochlorite,  104 
Properties  of  minerals,  1 
Proustite,  137—196,  216 
Psilomelane,  22,  132—208 
Purple  copper,  24 
Purpurite,  228 

Pyrargyrite,  129,  139—198,  216 
Pyrite,  26—200 
Pyrites,  26 
Pyroelectricity,  10 
Pyrolusite,  17,  18—208 
Pyromorphite,  51,  71,  97, 122, 141—214 


Pyrope,  101—244 

Pyrophyllite,  29,  57,  75,  104—256 

Pyroxene,  62,  67,  83,  89,  111,  132,  143, 

149—220,  240 
Pyroxene  group : 
Aegirite,  63,  84,  113—222,  240 
Augite,  62,  67,  83,  89,  111,  132,  143, 

149—222,  240 
Bronzite,  36 
Diallage,  62 

Diopside,  36,  43,  62,  67,  111—240 
Enstatite,  36,  43,  83,  90,  111—240, 

258 

Fowlerite,  83 
Hedenbergite,  62,  67,  83,  89,  111, 

132,  143,  149—220,  240 
Hypersthene,  59,  67,  79,  91, 107,  111, 

132,  143—222,  258 
Jadeite,  54 
Jeffersonite,  240 
Pyroxene,  62,  67,  83,  89,  111,  132, 

143,  149—220,  240 
Rhodonite,  83,  111—240 
Spodumene,  38,  64,   84,   113—240, 

242 

Wollastonite,  35,  81—234 
Pyrrhotine,  25 
Pyrrhotite,  25—200 

Quartz,  55,  73,  102,  126—262 
Quicksilver,  26 

Reactions  of  the  elements,  174 

Reagents,  154 

Realgar,  136—212 

Records,  laboratory,  192 

Red  cobalt,  137 

Red  copper  ore,  141 

Red  iron  ore,  144 

Red  ocher,  144 

Red  oxide  of  copper,  141 

Red  zinc  ore,  141 

Reddle,  144 

Redruthite,  19 

Reducing  flame,  157,  158 

Reduction  of  metals,  162 

Rensselaerite,  29 

Resin  opal,  54 

Retinite,  95 

Rhodochrosite,  42,  88—248 

Rhodonite,  83,  111—240 


296 


INDEX 


Roasting  on  charcoal,  160 

Rock,  definition  of,  1 

Rock  crystal,  55 

Rock  salt,  39 

Roscoelite,  76,  105,  146—236 

Rose  beryl,  127 

Rose  quartz,  55 

Rosin  jack,  88 

Rubellite,  74 

Rubicelle,  127 

Ruby,  45 

Ruby  copper,  141 

Ruby  silver,  129,  137 

Ruby  spinel,  127 

Rutile,  72,  100,  134,  145—210,  262 

Sal  soda,  224 

Salt,  39 

Salt  of  phosphorus,  155 

bead  of,  168,  171 
Saltpeter,  48 

Samarskite,  133—204,  242 
Sanidine,  37 
Saponite,  256 
Sapphire,  45 
Sard,  55 
Sardonyx,  56 
Sassolite,  29,  75—228 
Satin  spar,  30 
Scale  of  fusibility,  159 

of  hardness,  7 
Scapolite,  44 
Scheelite,  43,  89,  116,  141—234,  254, 

258 

Schorl,  74 

Schorlomite,  102—232 
Scolecite,  36—230 
Scorodite,  52,  71,  97,  122,  148—218 
Selenite,  30 

Selenium,  tests  for,  184 
Senarmontite,  49,  70—212 
Sepiolite,  49,  94—232,  254 
Sericite,  30 
Serpentine,   51,    70,   96,    122—232, 

254 
Siderite,  41,  66,  87,  129,  140—218, 

248 

Silicates,  bases  in,  185 
Siliceous  sinter,  54,  56 
Silicon,  tests  for,  185 
Sillimanite,  33,  79,  108—260 


Silver,  27—202 

amalgam,  28 

glance,  18 

nitrate,  156,  173 

tests  for,  186 
Smaltite,  16—196 
Smithsonite,  43,  53,  89,  98,  117,  123 

—248,  252 
Smoky  quartz,  55 
Soapstone,  29 
Soda,  154 

bead,  170 

feldspar,  238 

mica,  31 

Soda  niter,  48,  94—224 
Soda-lime  feldspar,  37 
Sodalite,  53,  71,  99,  124—230 
Sodium,  ammonium  phosphate,  155 

carbonate,  154 

carbonate  bead,  170 

metaphosphate  bead,  168,  171 

phosphate,  156,  174 

tests  for,  186 

tetraborate,  154 
Soft  coal,  19 
Spathic  iron,  41 
Spearhead  pyrites,  26 
Specific  gravity,  8 
Specular  hematite,  134 

iron,  134 
Specularite,  134 
Spessartite,  102—240,  244 
Sphalerite,  41,  66,  88,  116,  129,  140— 

200,  228,  250,  254 
Sphene,  82 

Spinel,  74,  103,  127—262 
Spinel  ruby,  127 

Spodumene,  38,  64,  84,  113—240,  242 
Stalactite,  stalagmite,  40 
Stannine,  15 

Stannite,  15,  21,  25—200 
Stannous  chloride,  156 
Staurolite,  74,  103—260 
Staurotide,  103 
Steatite,  29 
Stephanite,  18—198 
Stibnite,  18—198 
Stilbite,  32,  78—234 
Streak,  9 

plate,  154 
Stream  tin,  100 


INDEX 


297 


Stromeyerite,  20 — 200 
Strontianite,  34,  61,  80,  109—246 
Strontian  spar,  34 
Strontium,  tests  for,  186 
Sublimates  in  closed  tube,  166 

in  open  tube,  167 

on  charcoal,  163,  164 

on  plaster,  164 
Succinite,  95 
Sulphates,  tests  for,  187 
Sulphides,  tests  for,  187 
Sulphur,  48,   94,   120,   128,   137—212 

tests  for,  187 
Sulphuric  acid,  155,  174 
Sunstone,  37 
Sussexite,  228 
Sylvanite,  14,  26—206 
Sylvite,  39,  65,  86,  114—224 
Systems  of  crystallization,  1 

Tabular  spar,  35 

Tables,  crystallographic,  266 

determinative,  12,  191,  266 

of  bead  tests,  169,  170,  171 

of  flame  colors,  161 

of  sublimates,  163,  164,  166,  167 
Talc,  29,  32,  57,  59,  104,  107—236,  246, 

256 

Tantalite,  23, 134—210,  264 
Tarnish,  9 
Taste,  10 
Tellurim,  27—206 

tests  for,  188 
Tennantite,  21,  129—196 
Tenacity,  8 
Tenorite,  21 
Tephroite,  63,  83—230 
Test  tubes,  154 

holder,  153,  154 

support,  154 
Tetradymite,  202,  206 
Tetragonal  system,  2,  3,  267 
Tetrahedrite,  21,  129—198 
Texasite,  147 
Thaumasite,  246 
Thenardite,  31,  77—224 
Thinolite,  40 

Thomsonite,  53,  99,  123—230 
Thorite,  130,  142—252 
Thulite,  33 
Tiger  eye,  55 


Tin  and  zinc,  155 
Tin,  pyrites,  15 
tests  for,  188 
Tinkal,  30 
Tinstone,  100 
Titanic  iron,  22 
Titanite,  61,  82,  110—234,  246 
Titanium,  tests  for,  188 
Topaz,  33,  80,  109—260 
Touchstone,  56 
Tourmaline,    56,    74,    102,    126—222, 

242,  258 
Transparency,  9 
Travertine,  40 
Tremolite,  36,  62,  82—238 
Triclinic  system,  2,  5,  272 
Tridymite,  56—264 
Trimorphism,  11 
Triphylite,  218 
Triplite,  218 
Tripoli,  46 
Tripolite,  46 
Trona,  32,  78—224 
Troostite,  44,  90,  117—230 
Tungsten,  tests  for,  189 
Turgite,  133,  135,  144—204,  208,  218, 

250 

Turkis,  turkish  stone,  124 
Turner's  flux,  155 
Turquois,  124,  149—250,  256,  260 
Tweezers,  or  forceps,  152,  153 
Twinning,  2 

Ulexite,  46—228 

Uraninite,  22,  133,  149—210 

Uranium,  tests  for,  189 

Uranothorite,  130 

Urao,  32 

Uvarovite,  102—244,  262 


Vanadinite,  96,  139—214 
Vanadium  mica,  105 
Vanadium,  tests  for,  189 
Variegated  copper,  24 
Verdantique,  122 
Vermiculite,  75,  104—232 
Vesuvianite,  101,  125—244 
Vivianite,  30,  58,  104,  146—218 
Von  Kobell's  flux,  155 
scale  of  fusibility,  159 


298 


INDEX 


Wad,  17,  21,  22—208,  250 

Waringtonite,  147 

Watch  glasses,  154 

Water,  155 

Water  sapphire,  108 

Wavellite,  52,  97,  122—252,  256 

Wernerite,  44,  90,  117—234,  244 

Wheel  ore,  20 

White  iron,  26 

White  iron  pyrites,  26 

White  lead  ore,  51 

White  mica,  30 

Whitneyite,  196 

Willemite,  44,  90,  117—232,  252 

Witherite,  51,  71,  97—226 

Wolfram,  21 

Wolframite,  21,  25,  131, 142—204,  222, 

242 

Wollastonite,  35, 81—234 
Wood  copper,  146 

opal,  54 

tin,  100 

Wulfenite,  50,  96, 121—214 
Wurtzite,  130,  140—200,  228,  250,  254 

Xenotime,  35,  81,  130,  141—256 

Yellow  copper,  24 
Yellow  ocher,  142 


Yttrotantalite,  258,  260 

Zaratite,  147—248 
Zeolites: 

Analcite,  53,  98,  123—232 

Apophyllite,  33,  79,  107—234 

Chabazite,  42,  89—234 

Gmelinite,  232,  234 

Harmotome,  34,  81—232,  244 

Heulandite,  32,  78—234 

Laumontite,  41,  88 — 230 

Mesolite,  230 

Natrolite,  35,  82—230 

Phillipsite,  34,  81—232 

Scolecite,  36—230 

Stilbite,  32,  78—234 

Thomsonite,  53,  99,  123—230 
Zinc  and  tin,  155 
Zinc,  blende,  88 

bloom,  49 

rhodonite,  240 

spinel,  262 

tests  for,  189 
Zincite,  141—250 
Zinkenite,  198 
Zinnwaldite,  220 
Zircon,  56,  74,  103,  126—262 
Zirconium,  tests  for,  190 
Zoisite,  33,  60,  79,  107—246 


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